GHSA-f7ph-p5rv-phw2 — nunjucks
GHSA-f7ph-p5rv-phw2 is a Cross-site Scripting (XSS) vulnerability in nunjucks. 3 public exploit references exist, so weaponization risk is real. A fix is available for nunjucks — see the affected versions and patch details below.
Cross-Site Scripting in nunjucks
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
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 | 2.4.3npm install nunjucks@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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-f7ph-p5rv-phw2 can be triaged on real exposure rather than presence alone.
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 Security finds GHSA-f7ph-p5rv-phw2 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.