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Security Advisories: GSA_kwCzR0hTQS14NzdqLXc3d2YtZmptd84AAy5c

Nunjucks autoescape bypass leads to cross site scripting

Impact

In Nunjucks versions prior to version 3.2.4, it was possible to bypass the restrictions which are provided by the autoescape functionality. If there are two user-controlled parameters on the same line used in the views, it was possible to inject cross site scripting payloads using the backslash \ character.

Example

If the user-controlled parameters were used in the views similar to the following:

<script>
let testObject = { lang: '{{ lang }}', place: '{{ place }}' };
</script>

It is possible to inject XSS payload using the below parameters:

https://<application-url>/?lang=jp\&place=};alert(document.domain)//

Patches

The issue was patched in version 3.2.4.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1825980

Permalink: https://github.com/advisories/GHSA-x77j-w7wf-fjmw
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS14NzdqLXc3d2YtZmptd84AAy5c
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: about 2 months ago
Updated: about 2 months ago

Identifiers: GHSA-x77j-w7wf-fjmw, CVE-2023-2142
References:

• https://github.com/mozilla/nunjucks/security/advisories/GHSA-x77j-w7wf-fjmw
• https://github.com/mozilla/nunjucks/pull/1437
• https://github.com/mozilla/nunjucks/commit/ec16d210e7e13f862eccdb0bc9af9f60ff6749d6
• https://bugzilla.mozilla.org/show_bug.cgi?id=1825980
• https://github.com/mozilla/nunjucks/releases/tag/v3.2.4
• https://github.com/advisories/GHSA-x77j-w7wf-fjmw

Affected Packages