GHSA-q3gh-5r98-j4h3 is a critical-severity (CVSS 9.8) Buffer Overflow vulnerability in jsrsasign. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-q3gh-5r98-j4h3 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.
jsrsasignnpmDescription
Impact
Jsrsasign can verify RSA-PSS signature which value can expressed as BigInteger. When there is a valid RSA-PSS signature value, this vulnerability is also accept value with prepending zeros as a valid signature.
- If you are not use RSA-PSS signature validation, this vulnerability is not affected.
- Risk to accept a forged or crafted message to be signed is low.
- Risk to raise memory corruption is low since jsrsasign uses BigInteger class.
Patches
Users using RSA-PSS signature validation should upgrade to 8.0.17.
Workarounds
Reject RSA-PSS signatures with unnecessary prepending zeros.
References
https://github.com/kjur/jsrsasign/security/advisories/GHSA-q3gh-5r98-j4h3 https://github.com/kjur/jsrsasign/issues/438 https://nvd.nist.gov/vuln/detail/CVE-2020-14968 https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-14968 https://vuldb.com/?id.157125 https://kjur.github.io/jsrsasign/api/symbols/RSAKey.html#.verifyWithMessageHashPSS
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsrsasign | ≥ 3.0.0&&< 8.0.17 | 8.0.17 |
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 jsrsasign. 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 jsrsasign to 8.0.17 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-q3gh-5r98-j4h3 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-q3gh-5r98-j4h3 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-q3gh-5r98-j4h3. 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-q3gh-5r98-j4h3 in your dependencies?
O3 detects GHSA-q3gh-5r98-j4h3 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.