Versions of mustache prior to 2.2.1 are affected by a cross-site scripting vulnerability when attributes in mustache templates are not quoted.

Example

Template:
<a href={{foo}}/>

Input:
{ 'foo' : 'test.com onload=alert(1)'}

Rendered result:
<a href=test.com onload=alert(1)/>

Recommendation

Update to version 2.2.1 or later.
Alternatively, ensure that all attributes in hmustache templates are encapsulated with quotes.

References

• https://nvd.nist.gov/vuln/detail/CVE-2015-8862
• janl/mustache.js@378bcca
• GHSA-w3w8-37jv-2c58
• https://www.npmjs.com/advisories/62
• https://www.tenable.com/security/tns-2016-18
• http://www.openwall.com/lists/oss-security/2016/04/20/11
• http://www.securityfocus.com/bid/96436