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
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | nunjucks | < 3.2.4 | 3.2.4 |
References
- https://github.com/mozilla/nunjucks/security/advisories/GHSA-x77j-w7wf-fjmw
- https://nvd.nist.gov/vuln/detail/CVE-2023-2142
- 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
- https://github.com/mozilla/nunjucks/releases/tag/v3.2.4
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- Weakness (CWE)
CWE-79- Platform
- npm
- Package
nunjucks- Disclosed
- 20.04.2023
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-x77j-w7wf-fjmw - CC BY 4.0
Vulnerability history: nunjucks
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 2
- First → latest
- 11.2018 04.2023
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Medium 2
Disclosures per year
- 2018: 1
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 1
- 2024: 0
- 2025: 0
- 2026: 0
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