MediumGHSA-x77j-w7wf-fjmwCVE-2023-2142

Nunjucks autoescape bypass leads to cross site scripting

Published 20 Apr 2023 · Updated 26 Nov 2024

Affected package

Affected: <3.2.4
Fixed in: 3.2.4

Update to the fixed version for your release line, for example:npm install nunjucks@3.2.4

Details

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

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References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.