CVE-2020-14968
CRITICALCVE-2020-14968 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 CVE-2020-14968 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
An issue was discovered in the jsrsasign package before 8.0.17 for Node.js. Its RSASSA-PSS (RSA-PSS) implementation does not detect signature manipulation/modification by prepending '\0' bytes to a signature (it accepts these modified signatures as valid). An attacker can abuse this behavior in an application by creating multiple valid signatures where only one signature should exist. Also, an attacker might prepend these bytes with the goal of triggering memory corruption issues.
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 CVE-2020-14968 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 CVE-2020-14968 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 CVE-2020-14968. 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-2020-14968 in your dependencies?
O3 detects CVE-2020-14968 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.