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Stored XSS in October

Low severity GitHub Reviewed Published Jun 2, 2020 in octobercms/october • Updated Jan 31, 2023

Package

composer october/backend (Composer)

Affected versions

>= 1.0.319, < 1.0.466

Patched versions

1.0.466

Description

Impact

A user with access to a markdown FormWidget that stores data persistently could create a stored XSS attack against themselves and any other users with access to the generated HTML from the field.

Patches

Issue has been patched in Build 466 (v1.0.466) & RainLab.Blog v1.4.1 by restricting the ability to store JS in markdown to only users that have been explicitly granted the backend.allow_unsafe_markdown permission.

Workarounds

Apply octobercms/october@9ecfb48 & rainlab/blog-plugin@6ae19a6 to your installation manually if unable to upgrade to Build 466 or v1.4.1 of RainLab.Blog (if using that plugin).

References

Reported by Sivanesh Ashok

For more information

If you have any questions or comments about this advisory:

Threat assessment:

Screen Shot 2020-03-31 at 2 01 52 PM

### References - https://github.com/octobercms/october/security/advisories/GHSA-w4pj-7p68-3vgv - https://nvd.nist.gov/vuln/detail/CVE-2020-11083 - https://github.com/octobercms/october/commit/9ecfb4867baae14a0d3f99f5b5c1e8a979ae8746 - https://github.com/rainlab/blog-plugin/commit/6ae19a6e16ef3ba730692bc899851342c858bb94 - http://packetstormsecurity.com/files/158730/October-CMS-Build-465-XSS-File-Read-File-Deletion-CSV-Injection.html - http://seclists.org/fulldisclosure/2020/Aug/2
@LukeTowers LukeTowers published to octobercms/october Jun 2, 2020
Published by the National Vulnerability Database Jul 14, 2020
Reviewed Jul 28, 2020
Published to the GitHub Advisory Database Aug 5, 2020
Last updated Jan 31, 2023

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
Required
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N

EPSS score

0.390%
(74th percentile)

Weaknesses

CVE ID

CVE-2020-11083

GHSA ID

GHSA-w4pj-7p68-3vgv

Source code

No known source code

Credits

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