GHSA-76c9-3jph-rj3q is a low-severity (CVSS 3.4) CWE-241 vulnerability in on-headers. A fix is available for on-headers — see the affected versions and patch details below.
on-headers is vulnerable to http response header manipulation
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for GHSA-76c9-3jph-rj3q.
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.
How urgent is this, really
GHSA-76c9-3jph-rj3q plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
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.
on-headersnpmDescription
Impact
A bug in on-headers versions < 1.1.0 may result in response headers being inadvertently modified when an array is passed to response.writeHead()
Patches
Users should upgrade to 1.1.0
Workarounds
Uses are encouraged to upgrade to 1.1.0, but this issue can be worked around by passing an object to response.writeHead() rather than an array.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | on-headers | all versions | 1.1.0npm install on-headers@1.1.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for on-headers, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update on-headers to 1.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-76c9-3jph-rj3q 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-76c9-3jph-rj3q can be triaged on real exposure rather than presence alone.
Tailored to GHSA-76c9-3jph-rj3q. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Openshift Data Foundation 4.20 | odf4/cephcsi-rhel9:v4.20-1761848902 | RHSA-2025:21704 |
Frequently Asked Questions
Is GHSA-76c9-3jph-rj3q in your dependencies?
O3 Security finds GHSA-76c9-3jph-rj3q across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.