GHSA-c9g6-9335-x697 is a medium-severity (CVSS 5.3) CWE-755 vulnerability in sockjs. 4 public exploit references exist, so weaponization risk is real. A fix is available for sockjs — see the affected versions and patch details below.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-c9g6-9335-x697 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
sockjsnpmDescription
Incorrect handling of Upgrade header with the value websocket leads in crashing of containers hosting sockjs apps. This affects the package sockjs before 0.3.20.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | sockjs | all versions | 0.3.20npm install sockjs@0.3.20 |
Affected Products
sockjssockjs_projectResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Incorrect handling of Upgrade header with the value websocket leads in c…
Incorrect handling of Upgrade header with the value websocket leads in c…
Incorrect handling of Upgrade header with the value websocket leads in c…
Incorrect handling of Upgrade header with the value websocket leads in c…
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sockjs, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sockjs to 0.3.20 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c9g6-9335-x697 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.
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.
There is no mitigation for this issue, the flaw can only be resolved by applying updates.Source: Red Hat security advisory for GHSA-c9g6-9335-x697 (CC BY 4.0)
Frequently Asked Questions
Is GHSA-c9g6-9335-x697 in your dependencies?
Find it across npm, including transitive dependencies.