diff --git a/CHANGES.txt b/CHANGES.txt
index 2170eed1..106e9aa6 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -16,6 +16,21 @@ python 3.6 or newer (3.4/3.5 might work, but they are not tested).
 
 Fixed:
 
+- CVE-2024-39124 - The classhelpers (_generic.help.html) are
+  vulnerable to an XSS attack. A specially crafted URL that used
+  that endpoint would result in running a script embedded in the
+  URL. (Found/reported by Alec Romano (4rdr), fix/tests John
+  Rouillard)
+- CVE-2024-39125 - If the Referer header is set to a script tag,
+  it will be executed when the error in the Referer header is
+  reported. (Found/reported by Alec Romano (4rdr), fix/tests John
+  Rouillard)
+- CVE-2024-39126 - PDF, XML and SVG files attached to an issue can contain
+  embedded JavaScript. This JavaScript was executed when the file was
+  accessed. PDF files are now downloaded and not displayed in the
+  browser. A content security policy is added for all download files
+  which prevents code execution in SVG files.  (Found/reported by Alec
+  Romano (4rdr), fix/tests John Rouillard)
 - issue2551282 - MySQL utf8mb4 issues and
   issue2551115 - Use utf8mb4 as a default for MySQL instead of utf8
   The default database type and collations have been set to:
diff --git a/doc/CVE.txt b/doc/CVE.txt
new file mode 100644
index 00000000..10b72530
--- /dev/null
+++ b/doc/CVE.txt
@@ -0,0 +1,100 @@
+.. comments:
+   This file is a temporary way to post CVE notifications before
+   a release.
+
+   Document the CVE fix info in upgrading.txt. Publishing
+   upgrading.txt would push info on the next release not the current
+   release.
+
+   So we comment out a reference anchor in upgrading.txt and use that
+   comment to extract the section from upgrading.txt into CVE.txt.
+   The extracted section gets the same anchor that is in upgrading.txt,
+   but is is not commented out.
+
+   Then we add a summary to the list of CVE's in security.txt using a
+   :ref: to the anchor. If CVE.txt is part of the build and
+   upgrading.txt has a commented out anchor, security.txt entries link
+   to CVE.html in the generated documentation.
+
+   In upgrading.txt add a
+
+   .. comment: _CVE-2024-39124:
+
+   before the section for the CVE (use the real CVE number). At the
+   end of the CVE section add an end comment:
+
+   .. comment: end of CVE include marker
+
+   Update security.txt with a :ref: to the CVE section. E.G. a
+   security.txt references look like:
+
+     * `CVE-2024-39124`_ - :ref:`classhelpers (_generic.help.html) are
+    vulnerable to an XSS attack. <CVE-2024-39124>` Requires fixing
+    tracker homes.
+
+   where <CVE-2024-39124> is the reference. The same reference anchor
+   is present (commented out) in upgrading.txt. In CVE.txt you
+   replicate the existing anchor and include to extract the content
+   section from upgrading.txt. E.G.
+
+   .. _CVE-2024-39124:
+
+   .. include:: upgrading.txt
+      :start-after: .. comment: _CVE-2024-39124:
+      :end-before: .. comment: end of CVE
+
+   After building the docs, install docs/security.html and
+   docs/CVE.html on the web site. Use the security.html URL
+   on the web site to update the CVE report.
+
+   When the release is ready, replace 'comment: _CVE' with '_CVE' in
+   upgrading.txt. This makes the anchors in upgrading.txt live.
+
+    Then disable CVE.txt by removing CVE.txt from contents.txt in the
+   toctree hidden section. Also add CVE.txt to exclude_patterns in
+   conf.py.
+
+   No change needs to happen to security.txt as it's using a :ref: and
+   we just changed the location for the ref so sphinx will get the
+   links correct.
+
+   Now build the docs and publish to the web site.
+
+===========
+Roundup CVE
+===========
+
+This is a list of remediation for CVE's that are not fixed in the
+latest release. When the latest release fixes the CVE, see `the
+upgrading doc <upgrading.html>`_ for these details.
+
+.. contents::
+   :local:
+   :depth: 2
+
+.. _CVE-2024-39124:
+
+.. note::
+
+   Prior to the release of Roundup 2.4.0, you can access updated
+   tracker templates that address CVE-2024-39124 from
+   `CVE-2024-39124-templates.zip
+   <../CVE-2024-39124-templates.zip>`_. Download and extract the zip
+   file to generate a templates subdirectory containing the classic,
+   minimal and other tracker templates.
+
+.. include:: upgrading.txt
+   :start-after: .. comment: _CVE-2024-39124:
+   :end-before: .. comment:
+
+.. _CVE-2024-39125:
+
+.. include:: upgrading.txt
+   :start-after: .. comment: _CVE-2024-39125:
+   :end-before: .. comment:
+
+.. _CVE-2024-39126:
+
+.. include:: upgrading.txt
+   :start-after: .. comment: _CVE-2024-39126:
+   :end-before: .. comment: end of CVE include marker
diff --git a/doc/acknowledgements.txt b/doc/acknowledgements.txt
index 54663e5a..0db8ae3c 100644
--- a/doc/acknowledgements.txt
+++ b/doc/acknowledgements.txt
@@ -40,6 +40,8 @@ Norbert Schlemmer - docker support
 Bharath Kanama, Nikunj Thakkar, Patel Malav - classhelper web
 component development.
 
+Alec Romano (4rdr) - identified multiple security issues
+
 2.3
 ---
 
diff --git a/doc/announcement.txt b/doc/announcement.txt
index 800beb22..82214502 100644
--- a/doc/announcement.txt
+++ b/doc/announcement.txt
@@ -4,7 +4,7 @@ release, so make sure to read `docs/upgrading.txt
 <https://www.roundup-tracker.org/docs/upgrading.html>`_ to
 bring your tracker up to date.
 
-The 67 changes, as usual, include some new features and many
+The 79 changes, as usual, include some new features and many
 bug fixes.
 
 Note that you should run ``roundup-admin ... migrate`` to
@@ -22,12 +22,16 @@ You can install it with::
 
 then unpack and test/install from the tarball.
 
-Beta 2 includes a small change to the classic tracker's
-classhelper.js to fix a bug found after beta 1 was released.
-
 Among the notable improvements in 2.4.0 from the 2.3.0
 release are:
 
+* three CVE's have been fixed. One requires changes to your
+  tracker's home directory. The other two are fixed by
+  installing 2.4.0.  See
+  https://www.roundup-tracker.org/docs/security.html for
+  details and instructions on how to fix these in 2.4.0 and
+  earlier releases.
+
 * new classhelper component thanks to a team of students
   from CS682 at U-Mass Boston. This fixes many issues with
   the old classhelper. It is implemented as a web-component
@@ -87,7 +91,7 @@ release are:
 * sqlite version 1 and StructuredText support removed.
 
 The file CHANGES.txt has a detailed list of feature
-additions and bug fixes (67) for each release. The most
+additions and bug fixes for each release. The most
 recent changes from there are at the end of this
 announcement. Also see the information in doc/upgrading.txt.
 
diff --git a/doc/security.txt b/doc/security.txt
index 89676352..e9756e00 100644
--- a/doc/security.txt
+++ b/doc/security.txt
@@ -1,20 +1,51 @@
 .. meta::
     :description:
         Documentation on how to report security issues with
-        Roundup. Also index to security related portions in other
-        Roundup documentation. How to verify distribution using gpg.
+        Roundup. Index to recent security related (CVE) descriptions
+        in other Roundup documentation. How to verify distribution
+        using gpg.
 
 .. index::
    single: Reporting Security Issues
+   single: CVE announcements
    single: Security Issues, Reporting
+   single: Security Issues, Remediation
+   single: Security Issues, CVE announcements
 
 
 =======================
 Roundup Security Issues
 =======================
 
-This page documents how to report security issues and verify the
-signatures for Roundup releases.
+This page documents CVE's fixed starting with version 2.4.0, how to
+report security issues, and verify the signatures for Roundup
+source release tarballs.
+
+.. contents::
+   :local:
+   :depth: 2
+
+CVE Announcements
+-----------------
+
+  * `CVE-2024-39124`_ - :ref:`classhelpers (_generic.help.html) are
+    vulnerable to an XSS attack. <CVE-2024-39124>` Requires fixing
+    tracker homes.
+  * `CVE-2024-39125`_ - :ref:`if Referer header is set to a script tag,
+    it will be executed. <CVE-2024-39125>` Fixed in release 2.4.0,
+    directions available for fixing in prior versions.
+  * `CVE-2024-39126`_ - :ref:`PDF, XML and SVG files downloaded from an
+    issue can contain embedded JavaScript which is
+    executed. <CVE-2024-39126>` Fixed in release 2.4.0, directions
+    available for fixing in prior versions.
+
+.. _CVE-2024-39124:
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-39124
+.. _CVE-2024-39125:
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-39125
+.. _CVE-2024-39126:
+        https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-39126
+
 
 Reporting Security Issues
 -------------------------
@@ -88,8 +119,8 @@ Once you have loaded the public key, you need a detached signature for
 your release.
 
 
-Download and Verify with Detached Signature
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Download Detached Signature and Verify
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 This needs to be done once for each release you wish to verify.
 
@@ -137,5 +168,6 @@ If something is wrong you will see::
   gpg:                using RSA key 411E354B5D1AF26125D621221F2DD0CB756A76D8
   gpg: BAD signature from "Roundup Team (signing key for roundup releases) <roundup-devel at lists.sourceforge.net>"
 
-**do not use** the tarball if the signature is BAD. Email the
-roundup-devel mailing list if you have this happen to you.
+**do not use** the tarball if the signature is BAD. Email the mailing
+list: roundup-devel at lists.sourceforge.net if you have this happen
+to you.
diff --git a/doc/upgrading.txt b/doc/upgrading.txt
index 6ada66a4..e1d6f32f 100644
--- a/doc/upgrading.txt
+++ b/doc/upgrading.txt
@@ -122,12 +122,290 @@ This will insert the bad API login rate limiting settings.
 Also if you have ``html_version`` set to ``xhtml``, you will get
 an error.
 
-Use of xhtml html_version disabled (required)
----------------------------------------------
+.. comment: _CVE-2024-39124:
 
-If you enabled xhtml formatted templates, you will need to
-change them to html (html4) format. Also change the value of
-``html_version`` from ``xhtml`` to ``html``.
+Fix for CVE-2024-39124 in help/calendar popups (recommended)
+------------------------------------------------------------
+
+Classhelper components accessed via URL using ``@template=help``,
+``@template=calendar`` or other template frame in the classhelper
+can run JavaScript embedded in the URL. If user clicks on a
+malicious URL that:
+
+  * arrives in an email,
+  * is embedded in a note left on a ticket [#markdown-note]_,
+  * left on some other web page
+
+the JavaScript code will be executed. This vulnerability seems to
+be limited to manually crafted URL's. It has not been generated
+by using Roundup's mechanism for generating classhelper URLs.
+
+The files that need to be changed to fix this depend on the
+template used to create the tracker.  Check the
+TEMPLATE-INFO.txt file in your tracker home. The template
+name is the first component of the ``Name`` field. For
+example trackers with Names like::
+
+   Name: classic-bugtracker
+
+   Name: devel-mytracker
+
+were derived from the ``classic`` and ``devel`` templates
+respectively. If your tracker is derived from the jinja2
+template, you may not be affected as it doesn't provide
+classhelpers by default. If you aren't sure which tracker
+template was used to create your tracker home, check the
+``html/help.html`` file for the word ``Javascript``. If your
+help.html is missing the word ``Javascript``, follow the
+directions for the classic template.
+
+If you have not modified the original tracker html
+templates, you can copy replacement files from the new
+templates supplied with release 2.4.0.  If you install 2.4.0
+in a `new virtual environment
+<installation.html#standard-installation>`_, you can use the
+command ``roundup-admin templates`` to find the installation
+path of the default templates.
+
+If your template was based on the classic template, replace the 
+following files in your tracker:
+
+  * html/_generic.calendar.html
+  * html/_generic.help-list.html
+  * html/_generic.help-submit.html
+  * html/_generic.help.html
+  * html/user.help-search.html
+  * html/user.help.html
+
+If your template was based on the minimal template, replace the 
+following files in your tracker:
+
+  * html/_generic.calendar.html
+  * html/_generic.help.html
+
+If your template was based on the responsive or devel templates,
+replace the following files in your tracker:
+
+  * html/_generic.calendar.html
+  * html/_generic.help-submit.html
+  * html/help.html
+  * html/user.help-search.html
+  * html/user.help.html
+
+As an example, assume Roundup's virtual environment is
+``/tools/roundup``. The classic tracker's default template will
+be in ``/tools/roundup/share/roundup/templates/classic``.
+Copy
+``/tools/roundup/share/roundup/templates/classic/html/_generic.calendar.html``
+to ``html/_generic.calendar.html`` in your tracker's home
+directory. Repeat for every one of the files that needs to
+be replaced.
+
+If you have made local changes to your popup/classhelper
+files or have created new help templates based on the
+existing ones, don't copy the default files. Instead, follow
+the directions below to modify each file as needed for your
+template.
+
+In the examples below, your script tag may differ. For
+example it could include::
+
+  tal:attributes="nonce request/client/client_nonce"
+
+If it does, keep the differences. You want to make changes
+to remove the structure option but keep the rest of the
+valid attributes.
+
+Most files have a small script that sets a few variables
+from the settings in the URL. You should change::
+
+       <script language="Javascript" type="text/javascript"
+           tal:content="structure string:
+           // this is the name of the field in the original form that we're working on
+           form  = window.opener.document.${request/form/form/value};
+           field  = '${request/form/property/value}';">
+
+to::
+
+       <script language="Javascript" type="text/javascript"
+           tal:content="string:
+           // this is the name of the field in the original form that we're working on
+           form  = window.opener.document.${request/form/form/value};
+           field  = '${request/form/property/value}';">
+
+by removing the ``structure`` keyword from the tal:content
+block. This will html escape the settings in the URL. This
+neutralizes an attempt to execute JavaScript by manipulating
+the URL. Most of the files use code similar to this.
+
+A few files have more extensive JavaScript embedded in the same
+script tag. To handle this you should split it into two scripts
+and encode the replaced strings. For example, change::
+
+      <script language="Javascript" type="text/javascript"
+          tal:content="structure string:<!--
+  // this is the name of the field in the original form that we're working on
+  form  = parent.opener.document.${request/form/form/value};
+  callingform=form
+  field  = '${request/form/property/value}';
+  var listform = null
+  function listPresent() {
+    return document.frm_help.cb_listpresent.checked
+  [more code skipped]
+
+to::
+
+      <script language="Javascript" type="text/javascript"
+          tal:content="string:
+  // this is the name of the field in the original form that we're working on
+  form  = parent.opener.document.${request/form/form/value};
+  callingform=form
+  field  = '${request/form/property/value}';">
+    </script>
+    <script language="Javascript" type="text/javascript"
+	    tal:content="string:
+  var listform = null
+  function listPresent() {
+    return document.frm_help.cb_listpresent.checked
+  [...]
+
+modifying the original by:
+
+ 1. removing the ``structure`` keyword and the HTML comment
+    marker ``<!--``. This encodes the replaced strings.
+ 2. adding ``">`` at the end of the line that sets ``field`` closes
+    the script tag.
+ 3. adding::
+
+      </script>
+            <script language="Javascript" type="text/javascript"
+	    tal:content="string:
+
+    after the line used in step 2, to ends the first script and
+    starts a new script.
+
+Just removing the ``structure`` directive is enough to fix the
+bug. Splitting the large script into two parts:
+
+ 1. one that has replaced strings with values taken from the URL
+ 2. one that has no replaced strings
+
+allows use of ``structure`` on the script with no replaced
+strings should it be required for your tracker.
+
+.. [#markdown-note] If you are using markdown formatting for your tracker's notes,
+   the user will see the markdown label rather than the long
+   (suspicious) URL. You may want to add something like::
+
+     a[href*=\@template]::after {
+         content: ' [' attr(href) ']';
+     }
+
+   to your css. This displays the URL inside square brackets if
+   the href has ``@template`` in it. It is placed after the link
+   label.
+
+Fix CVE in earlier versions of Roundup (recommended)
+----------------------------------------------------
+
+If you are upgrading to version 2.4.0, you can skip this
+section. These fixes are already present in 2.4.0.
+
+This section is for people who can not upgrade yet, and want
+to fix the issues.
+
+.. comment: _CVE-2024-39125:
+
+Referer value not escaped CVE-2024-39125
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Malicious JavaScript inserted into a page can change the value of
+the Referer header to include a script. If a link on that page
+points to a Roundup tracker, that script will be executed. The
+technique to change the header will result in a change of the URL
+in the browser's address bar, but this is easily missed.
+
+Fix this by editing ``cgi/client.py``, and change::
+
+  except (UsageError, Unauthorised) as msg:
+     csrf_ok = False
+     self.form_wins = True
+     self._error_message = msg.args
+
+to::
+
+  except (UsageError, Unauthorised) as msg:
+      csrf_ok = False
+      self.form_wins = True
+      self.add_error_message(' '.join(msg.args))
+
+This escapes the Referer value an prevents it from being
+executed.
+
+.. comment: _CVE-2024-39126:
+
+Stop JavaScript execution from attached files CVE-2024-39126
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If an SVG, XML or PDF file that includes malicious JavaScript is
+attached to an issue, downloading the file will cause the
+JavaScript to run.
+
+In ``cgi/client.py`` add the Content-Security-Policy line
+after the existing ``nosniff`` line so it looks like::
+
+  # exception handlers.
+  self.determine_language()
+  self.db.i18n = self.translator
+  self.setHeader("X-Content-Type-Options", "nosniff")
+  self.setHeader("Content-Security-Policy", "script-src 'none'")
+  self.serve_file(designator)
+
+(the example is reindented for display).
+
+This should prevent SVG and XML files with embedded scripts
+from running.
+
+If your version of Roundup is old enough that the ``nosniff``
+line is missing, search for ``serve_file(designator)`` and add
+both setHeader lines.
+
+.. warning::
+
+  If your users use older browsers that don't support Content
+  Security Policies (e.g. Internet Explorer), you must
+  remove ``text/xml`` and ``image/svg`` from
+  ``mime_type_allowlist`` as explained below for
+  ``application/pdf``.
+
+PDF files can also embed JavaScript. Many browsers include
+PDF viewers that may not support disabling scripting.  The
+safest way to handle this is to force a download of the PDF
+file and use a PDF viewer with scripting disabled. To force
+downloading, look in ``cgi/client.py`` for
+``mime_type_allowlist`` and remove the line for
+``application/pdf``.
+
+Version 2.4.0 allows you to `modify the mime_type_allowlist
+using interfaces.py
+<admin_guide.html#controlling-browser-handling-of-attached-files>`_.
+This will allow you to enable in-browser reading of PDF
+files when you upgrade to 2.4.0 if you wish.
+
+Note that a `Content Security Policy as documented in the admin
+guide
+<admin_guide.html#adding-a-web-content-security-policy-csp>`_ is
+not applied it to a direct download. This requires adding an
+explicit CSP header as above.
+
+.. comment: end of CVE include marker
+
+XHTML no longer supported (required)
+------------------------------------
+
+If your ``config.ini`` sets ``html_version`` to ``xhtml``,
+you need to change it to ``html``. Then you need to change
+your tracker's templates to html from xhtml.
 
 Note that the default Roundup templates use html4 so it is
 unlikely that your templates are xhtml based. See
diff --git a/roundup/cgi/client.py b/roundup/cgi/client.py
index 86f84f19..30242142 100644
--- a/roundup/cgi/client.py
+++ b/roundup/cgi/client.py
@@ -835,7 +835,7 @@ def inner_main(self):
                 except (UsageError, Unauthorised) as msg:
                     csrf_ok = False
                     self.form_wins = True
-                    self._error_message = msg.args
+                    self.add_error_message(' '.join(msg.args))
 
                 # If csrf checks pass. Run actions etc.
                 # handle_action() may handle a form submit action.
@@ -873,7 +873,13 @@ def inner_main(self):
                 # exception handlers.
                 self.determine_language()
                 self.db.i18n = self.translator
+                # prevent application/octet-stream mime type in header
+                # from being changed to some other type by the browser
+                # when mime sniffing.
                 self.setHeader("X-Content-Type-Options", "nosniff")
+                # prevent script execution in downloaded SVG, XML files
+                # (or HTML files if enabled).
+                self.setHeader("Content-Security-Policy", "script-src 'none'")
                 self.serve_file(designator)
             except SendStaticFile as file:
                 self.serve_static_file(str(file))
diff --git a/share/roundup/templates/classic/html/_generic.calendar.html b/share/roundup/templates/classic/html/_generic.calendar.html
index 7d5d62a1..b2ae0a99 100644
--- a/share/roundup/templates/classic/html/_generic.calendar.html
+++ b/share/roundup/templates/classic/html/_generic.calendar.html
@@ -7,7 +7,7 @@
   <title tal:content="string:Roundup Calendar"></title>
   <script language="Javascript"
           type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field = '${request/form/property/value}';" >
diff --git a/share/roundup/templates/classic/html/_generic.help-list.html b/share/roundup/templates/classic/html/_generic.help-list.html
index a5b0d285..b525ff65 100644
--- a/share/roundup/templates/classic/html/_generic.help-list.html
+++ b/share/roundup/templates/classic/html/_generic.help-list.html
@@ -4,11 +4,10 @@
     <title>Search result for user helper</title>
     <link rel="stylesheet" type="text/css" href="@@file/style.css" />
     <script language="Javascript" type="text/javascript"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${request/form/form/value};
-        field  = '${request/form/property/value}';
-    //-->"></script>
+        field  = '${request/form/property/value}';"></script>
     <script src="@@file/help_controls.js" type="text/javascript"></script>
 <script type="text/javascript"><!--
 var text_field = parent.submit.document.frm_help.text_preview;
diff --git a/share/roundup/templates/classic/html/_generic.help-submit.html b/share/roundup/templates/classic/html/_generic.help-submit.html
index 6c477024..768bc994 100644
--- a/share/roundup/templates/classic/html/_generic.help-submit.html
+++ b/share/roundup/templates/classic/html/_generic.help-submit.html
@@ -6,11 +6,14 @@
       <tal:block tal:condition="python:'property' in request.form">
       <title>Generic submit page for framed helper windows</title>
       <script language="Javascript" type="text/javascript"
-          tal:content="structure string:<!--
+          tal:content="string:
 // this is the name of the field in the original form that we're working on
 form  = parent.opener.document.${request/form/form/value};
 callingform=form
-field  = '${request/form/property/value}';
+field  = '${request/form/property/value}';">
+</script>
+      <script language="Javascript" type="text/javascript"
+          tal:content="structure string:
 var listform = null
 function listPresent() {
   return document.frm_help.cb_listpresent.checked
@@ -35,8 +38,7 @@
   var bol= listform != null
   alert('checkListForm: bol='+bol)
   return bol
-}
-//-->">
+}">
       </script>
       <script src="@@file/help_controls.js" type="text/javascript"></script>
       </tal:block>
diff --git a/share/roundup/templates/classic/html/_generic.help.html b/share/roundup/templates/classic/html/_generic.help.html
index ae862149..d3c79d5c 100644
--- a/share/roundup/templates/classic/html/_generic.help.html
+++ b/share/roundup/templates/classic/html/_generic.help.html
@@ -9,7 +9,7 @@
        tal:content="property | default" i18n:translate="" /> help - <span i18n:name="tracker"
        tal:replace="config/TRACKER_NAME" /></title>
       <script language="Javascript" type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field  = '${request/form/property/value}';">
diff --git a/share/roundup/templates/classic/html/user.help-search.html b/share/roundup/templates/classic/html/user.help-search.html
index c3874bef..7ecf99cb 100644
--- a/share/roundup/templates/classic/html/user.help-search.html
+++ b/share/roundup/templates/classic/html/user.help-search.html
@@ -5,11 +5,10 @@
   <head>
     <title>Search input for user helper</title>
     <script language="Javascript" type="text/javascript"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${form};
-        field  = '${field}';
-        //-->">
+        field  = '${field}';">
     </script>
     <script type="text/javascript" src="@@file/help_controls.js"></script>
     <link rel="stylesheet" type="text/css" href="@@file/style.css" />
diff --git a/share/roundup/templates/classic/html/user.help.html b/share/roundup/templates/classic/html/user.help.html
index 55fc4265..3187cfde 100644
--- a/share/roundup/templates/classic/html/user.help.html
+++ b/share/roundup/templates/classic/html/user.help.html
@@ -14,11 +14,10 @@
 	       tal:replace="config/TRACKER_NAME" /></tal:x></title>
       <script language="Javascript" type="text/javascript"
 	      tal:condition=false
-          tal:content="structure string:<!--
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${form};
-          field  = '${field}';
-          //-->">
+          field  = '${field}';">
       </script>
       <script src="@@file/help_controls.js"
      tal:condition=false type="text/javascript"><!--
diff --git a/share/roundup/templates/devel/html/_generic.calendar.html b/share/roundup/templates/devel/html/_generic.calendar.html
index 7d5d62a1..b2ae0a99 100644
--- a/share/roundup/templates/devel/html/_generic.calendar.html
+++ b/share/roundup/templates/devel/html/_generic.calendar.html
@@ -7,7 +7,7 @@
   <title tal:content="string:Roundup Calendar"></title>
   <script language="Javascript"
           type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field = '${request/form/property/value}';" >
diff --git a/share/roundup/templates/devel/html/_generic.help-submit.html b/share/roundup/templates/devel/html/_generic.help-submit.html
index 6c477024..ddc028b2 100644
--- a/share/roundup/templates/devel/html/_generic.help-submit.html
+++ b/share/roundup/templates/devel/html/_generic.help-submit.html
@@ -6,11 +6,14 @@
       <tal:block tal:condition="python:'property' in request.form">
       <title>Generic submit page for framed helper windows</title>
       <script language="Javascript" type="text/javascript"
-          tal:content="structure string:<!--
+          tal:content="string:
 // this is the name of the field in the original form that we're working on
 form  = parent.opener.document.${request/form/form/value};
 callingform=form
-field  = '${request/form/property/value}';
+field  = '${request/form/property/value}';">
+      </script>
+      <script language="Javascript" type="text/javascript"
+          tal:content="string:
 var listform = null
 function listPresent() {
   return document.frm_help.cb_listpresent.checked
diff --git a/share/roundup/templates/devel/html/help.html b/share/roundup/templates/devel/html/help.html
index 743bb2f8..e80656bf 100644
--- a/share/roundup/templates/devel/html/help.html
+++ b/share/roundup/templates/devel/html/help.html
@@ -10,11 +10,10 @@
     <tal:x i18n:name="what" tal:content="what" i18n:translate="" />
     help - <span i18n:name="tracker" tal:replace="config/TRACKER_NAME" />
   </title>
-  <script language="Javascript" type="text/javascript" tal:content="structure string:<!--
+  <script language="Javascript" type="text/javascript" tal:content="string:
     // this is the name of the field in the original form that we're working on
     form  = window.opener.document.${form};
-    field  = '${field}';
-    //-->">
+    field  = '${field}';">
   </script>
   <link rel="stylesheet" type="text/css" href="@@file/help.css" />
   <script src="@@file/help_controls.js" type="text/javascript"></script>
diff --git a/share/roundup/templates/devel/html/user.help-search.html b/share/roundup/templates/devel/html/user.help-search.html
index c3874bef..7ecf99cb 100644
--- a/share/roundup/templates/devel/html/user.help-search.html
+++ b/share/roundup/templates/devel/html/user.help-search.html
@@ -5,11 +5,10 @@
   <head>
     <title>Search input for user helper</title>
     <script language="Javascript" type="text/javascript"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${form};
-        field  = '${field}';
-        //-->">
+        field  = '${field}';">
     </script>
     <script type="text/javascript" src="@@file/help_controls.js"></script>
     <link rel="stylesheet" type="text/css" href="@@file/style.css" />
diff --git a/share/roundup/templates/devel/html/user.help.html b/share/roundup/templates/devel/html/user.help.html
index 29b32897..82c999d3 100644
--- a/share/roundup/templates/devel/html/user.help.html
+++ b/share/roundup/templates/devel/html/user.help.html
@@ -6,7 +6,7 @@
                   field request/form/property/value">
   <tal:block metal:fill-slot="more-javascript">
      <script language="javascript" type="text/javascript"
-     tal:content="structure string:form  = parent.opener.document.${form};
+     tal:content="string:form  = parent.opener.document.${form};
       callingform=form;
       field  = '${field}';"></script>
      <script language="Javascript" type="text/javascript">
diff --git a/share/roundup/templates/minimal/html/_generic.calendar.html b/share/roundup/templates/minimal/html/_generic.calendar.html
index 74907ea1..9649f050 100644
--- a/share/roundup/templates/minimal/html/_generic.calendar.html
+++ b/share/roundup/templates/minimal/html/_generic.calendar.html
@@ -7,7 +7,7 @@
   <title tal:content="string:Roundup Calendar"></title>
   <script language="Javascript"
           type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field = '${request/form/property/value}';" >
diff --git a/share/roundup/templates/minimal/html/_generic.help.html b/share/roundup/templates/minimal/html/_generic.help.html
index ae862149..d3c79d5c 100644
--- a/share/roundup/templates/minimal/html/_generic.help.html
+++ b/share/roundup/templates/minimal/html/_generic.help.html
@@ -9,7 +9,7 @@
        tal:content="property | default" i18n:translate="" /> help - <span i18n:name="tracker"
        tal:replace="config/TRACKER_NAME" /></title>
       <script language="Javascript" type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field  = '${request/form/property/value}';">
diff --git a/share/roundup/templates/responsive/html/_generic.calendar.html b/share/roundup/templates/responsive/html/_generic.calendar.html
index 7d5d62a1..b2ae0a99 100644
--- a/share/roundup/templates/responsive/html/_generic.calendar.html
+++ b/share/roundup/templates/responsive/html/_generic.calendar.html
@@ -7,7 +7,7 @@
   <title tal:content="string:Roundup Calendar"></title>
   <script language="Javascript"
           type="text/javascript"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field = '${request/form/property/value}';" >
diff --git a/share/roundup/templates/responsive/html/_generic.help-submit.html b/share/roundup/templates/responsive/html/_generic.help-submit.html
index 6c477024..48498320 100644
--- a/share/roundup/templates/responsive/html/_generic.help-submit.html
+++ b/share/roundup/templates/responsive/html/_generic.help-submit.html
@@ -6,11 +6,14 @@
       <tal:block tal:condition="python:'property' in request.form">
       <title>Generic submit page for framed helper windows</title>
       <script language="Javascript" type="text/javascript"
-          tal:content="structure string:<!--
+          tal:content="string:
 // this is the name of the field in the original form that we're working on
 form  = parent.opener.document.${request/form/form/value};
 callingform=form
-field  = '${request/form/property/value}';
+field  = '${request/form/property/value}';">
+      </script>
+      <script language="Javascript" type="text/javascript"
+          tal:content="structure string:
 var listform = null
 function listPresent() {
   return document.frm_help.cb_listpresent.checked
diff --git a/share/roundup/templates/responsive/html/help.html b/share/roundup/templates/responsive/html/help.html
index de367c4d..23726b9f 100644
--- a/share/roundup/templates/responsive/html/help.html
+++ b/share/roundup/templates/responsive/html/help.html
@@ -18,11 +18,10 @@
     body { padding-top: 80px; padding-bottom: 40px; }
   </style>
   <link rel="stylesheet" href="@@file/bootstrap-responsive.min.css">
-  <script language="Javascript" type="text/javascript" tal:content="structure string:<!--
+  <script language="Javascript" type="text/javascript" tal:content="string:
     // this is the name of the field in the original form that we're working on
     form  = window.opener.document.${form};
-    field  = '${field}';
-    //-->">
+    field  = '${field}';">
   </script>
   <link rel="stylesheet" type="text/css" href="@@file/help.css" />
   <script src="@@file/help_controls.js" type="text/javascript"></script>
diff --git a/share/roundup/templates/responsive/html/user.help-search.html b/share/roundup/templates/responsive/html/user.help-search.html
index c3874bef..7ecf99cb 100644
--- a/share/roundup/templates/responsive/html/user.help-search.html
+++ b/share/roundup/templates/responsive/html/user.help-search.html
@@ -5,11 +5,10 @@
   <head>
     <title>Search input for user helper</title>
     <script language="Javascript" type="text/javascript"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${form};
-        field  = '${field}';
-        //-->">
+        field  = '${field}';">
     </script>
     <script type="text/javascript" src="@@file/help_controls.js"></script>
     <link rel="stylesheet" type="text/css" href="@@file/style.css" />
diff --git a/share/roundup/templates/responsive/html/user.help.html b/share/roundup/templates/responsive/html/user.help.html
index 29b32897..82c999d3 100644
--- a/share/roundup/templates/responsive/html/user.help.html
+++ b/share/roundup/templates/responsive/html/user.help.html
@@ -6,7 +6,7 @@
                   field request/form/property/value">
   <tal:block metal:fill-slot="more-javascript">
      <script language="javascript" type="text/javascript"
-     tal:content="structure string:form  = parent.opener.document.${form};
+     tal:content="string:form  = parent.opener.document.${form};
       callingform=form;
       field  = '${field}';"></script>
      <script language="Javascript" type="text/javascript">
diff --git a/test/test_cgi.py b/test/test_cgi.py
index aca56d4d..6ad4c27b 100644
--- a/test/test_cgi.py
+++ b/test/test_cgi.py
@@ -978,7 +978,7 @@ def wh(s):
         self.assertFalse('HTTP_PROXY' in cl.env)
         self.assertFalse('HTTP_PROXY' in os.environ)
 
-    def testCsrfProtection(self):
+    def testCsrfProtectionHtml(self):
         # need to set SENDMAILDEBUG to prevent
         # downstream issue when email is sent on successful
         # issue creation. Also delete the file afterwards
@@ -1058,6 +1058,17 @@ def hasPermission(s, p, classname=None, d=None, e=None, **kw):
         del(cl.env['HTTP_REFERER'])
         del(out[0])
 
+        # verify that HTTP_REFERER does not result in an XSS reflection
+        cl.env['HTTP_REFERER'] = '<script>alert(1)</script>'
+        cl.main()
+        match_at=out[0].find('<script>')
+        match_encoded_at=out[0].find('&lt;script&gt;')
+        print("\n\nresult of subtest 2a:", out[0])
+        self.assertEqual(match_at, -1) # must not find unencoded script tag
+        self.assertEqual(match_encoded_at, 53) # must find encoded script tag
+        del(cl.env['HTTP_REFERER'])
+        del(out[0])
+
         cl.env['HTTP_ORIGIN'] = 'http://whoami.com'
         cl.main()
         match_at=out[0].find('Redirecting to <a href="http://whoami.com/path/issue1?@ok_message')
diff --git a/test/test_liveserver.py b/test/test_liveserver.py
index ae4c4476..c909fb7c 100644
--- a/test/test_liveserver.py
+++ b/test/test_liveserver.py
@@ -263,6 +263,24 @@ def test_start_in_german(self):
         self.assertTrue(b'Aufgabenliste' in f.content)
         self.assertTrue(b'dauerhaft anmelden?' in f.content)
 
+    def test_classhelper_reflection(self):
+        """ simple test that verifies that the generic classhelper
+            is escaping the url params correctly.
+        """
+        f = requests.get(self.url_base() + "/keyword?@startwith=0&@template=help&properties=name&property=keyword&form=itemSynopsis</script><script>%3balert(1)%2f%2f&type=checkbox&@sort=name&@pagesize=50")
+        self.assertEqual(f.status_code, 200)
+        self.assertNotIn(b"<script>;alert(1)//;\n", f.content)
+        self.assertIn(
+            b"itemSynopsis&lt;/script&gt;&lt;script&gt;;alert(1)//;\n",
+            f.content)
+
+        f = requests.get(self.url_base() + "/keyword?@startwith=0&@template=help&properties=name&property=keyword</script><script>%3balert(1)%2f%2f&form=itemSynopsis&type=checkbox&@sort=name&@pagesize=50")
+        self.assertEqual(f.status_code, 200)
+        self.assertNotIn(b"<script>;alert(1)//;\n", f.content)
+        self.assertIn(
+            b"keyword&lt;/script&gt;&lt;script&gt;;alert(1)//';</script>\n",
+            f.content)
+
     def test_byte_Ranges(self):
         """ Roundup only handles one simple two number range, or
             a single number to start from:
@@ -1308,6 +1326,7 @@ def test_new_issue_with_file_upload(self):
         f = session.get(self.url_base()+'/file%(file)s/text1.txt'%m.groupdict())
         self.assertEqual(f.text, file_content)
         self.assertEqual(f.headers["X-Content-Type-Options"], "nosniff")
+        self.assertEqual(f.headers["Content-Security-Policy"], "script-src 'none'")
         print(f.text)
 
     def test_new_file_via_rest(self):
diff --git a/website/issues/html/_generic.calendar.html b/website/issues/html/_generic.calendar.html
index e12a2191..9b9a936c 100644
--- a/website/issues/html/_generic.calendar.html
+++ b/website/issues/html/_generic.calendar.html
@@ -8,7 +8,7 @@
   <script language="Javascript"
           type="text/javascript"
 	  tal:attributes="nonce request/client/client_nonce"
-          tal:content="structure string:
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field = '${request/form/property/value}';" >
diff --git a/website/issues/html/_generic.help-list.html b/website/issues/html/_generic.help-list.html
index 697b61d3..ee96842d 100644
--- a/website/issues/html/_generic.help-list.html
+++ b/website/issues/html/_generic.help-list.html
@@ -5,11 +5,10 @@
     <link rel="stylesheet" type="text/css" href="@@file/style.css" />
     <script language="Javascript" type="text/javascript"
         tal:attributes="nonce request/client/client_nonce"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${request/form/form/value};
-        field  = '${request/form/property/value}';
-    //-->"></script>
+        field  = '${request/form/property/value}';"></script>
     <script src="@@file/help_controls.js"
 	    tal:attributes="nonce request/client/client_nonce"
 	    type="text/javascript"></script>
diff --git a/website/issues/html/_generic.help-submit.html b/website/issues/html/_generic.help-submit.html
index d3b88550..911e3249 100644
--- a/website/issues/html/_generic.help-submit.html
+++ b/website/issues/html/_generic.help-submit.html
@@ -7,11 +7,14 @@
       <title>Generic submit page for framed helper windows</title>
       <script language="Javascript" type="text/javascript"
           tal:attributes="nonce request/client/client_nonce"
-          tal:content="structure string:<!--
+          tal:content="string:
 // this is the name of the field in the original form that we're working on
 form  = parent.opener.document.${request/form/form/value};
 callingform=form
-field  = '${request/form/property/value}';
+field  = '${request/form/property/value}';"></script>
+      <script language="Javascript" type="text/javascript"
+          tal:attributes="nonce request/client/client_nonce"
+          tal:content="string:
 var listform = null
 function listPresent() {
   return document.frm_help.cb_listpresent.checked
diff --git a/website/issues/html/_generic.help.html b/website/issues/html/_generic.help.html
index 71112457..c6b1731d 100644
--- a/website/issues/html/_generic.help.html
+++ b/website/issues/html/_generic.help.html
@@ -11,7 +11,7 @@
        tal:replace="config/TRACKER_NAME" /></title>
       <script language="Javascript" type="text/javascript"
 	      tal:attributes="nonce request/client/client_nonce"
-              tal:content="structure string:
+              tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${request/form/form/value};
           field  = '${request/form/property/value}';">
diff --git a/website/issues/html/user.help-search.html b/website/issues/html/user.help-search.html
index 16afdca5..4ef308cb 100644
--- a/website/issues/html/user.help-search.html
+++ b/website/issues/html/user.help-search.html
@@ -6,11 +6,10 @@
     <title>Search input for user helper</title>
     <script language="Javascript" type="text/javascript"
         tal:attributes="nonce request/client/client_nonce"
-        tal:content="structure string:<!--
+        tal:content="string:
         // this is the name of the field in the original form that we're working on
         form  = parent.opener.document.${form};
-        field  = '${field}';
-        //-->">
+        field  = '${field}';">
     </script>
     <script type="text/javascript" src="@@file/help_controls.js"
 	    tal:attributes="nonce request/client/client_nonce"></script>
diff --git a/website/issues/html/user.help.html b/website/issues/html/user.help.html
index 63bd27ac..9978b3a6 100644
--- a/website/issues/html/user.help.html
+++ b/website/issues/html/user.help.html
@@ -15,11 +15,10 @@
       <script language="Javascript" type="text/javascript"
 	      tal:attributes="nonce request/client/client_nonce"
 	      tal:condition=false
-          tal:content="structure string:<!--
+          tal:content="string:
           // this is the name of the field in the original form that we're working on
           form  = window.opener.document.${form};
-          field  = '${field}';
-          //-->">
+          field  = '${field}';">
       </script>
       <script src="@@file/help_controls.js"
 	      tal:attributes="nonce request/client/client_nonce"