GHSA-f7ph-p5rv-phw2
GHSA-f7ph-p5rv-phw2 is a Cross-site Scripting (XSS) vulnerability in nunjucks. 3 public exploit references exist, so weaponization risk is real. O3 Security confirms whether GHSA-f7ph-p5rv-phw2 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Cross-Site Scripting in nunjucks
Blast Radius
Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.
nunjucksnpmDescription
Affected versions of nunjucks do not properly escape specially structured user input in template vars when in auto-escape mode, resulting in a cross-site scripting vulnerability.
Proof of Concept
By using an array for the keys in a template var, escaping is bypassed.
name[]=<script>alert(1)</script>
A full PoC is available in the references section.
Recommendation
Update to version 2.4.3 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | nunjucks | all versions | 2.4.3 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nunjucks. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update nunjucks to 2.4.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-f7ph-p5rv-phw2 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-f7ph-p5rv-phw2 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-f7ph-p5rv-phw2. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-f7ph-p5rv-phw2 in your dependencies?
O3 detects GHSA-f7ph-p5rv-phw2 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.