CVE-2015-9235 — jsonwebtoken
Fix: auth0/node-jsonwebtoken@1bb584bCVE-2015-9235 is a Improper Input Validation vulnerability in jsonwebtoken. 4 public exploit references exist, so weaponization risk is real. A fix is available for jsonwebtoken — see the affected versions and patch details below.
Verification Bypass in jsonwebtoken
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.
jsonwebtokennpmDescription
Versions 4.2.1 and earlier of jsonwebtoken are affected by a verification bypass vulnerability. This is a result of weak validation of the JWT algorithm type, occuring when an attacker is allowed to arbitrarily specify the JWT algorithm.
Recommendation
Update to version 4.2.2 or later.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsonwebtoken | all versions | 4.2.2npm install jsonwebtoken@4.2.2 |
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 jsonwebtoken, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jsonwebtoken to 4.2.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2015-9235 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 CVE-2015-9235 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2015-9235. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2015-9235 in your dependencies?
O3 Security finds CVE-2015-9235 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.