CVE-2026-4598
Fix: kjur/jsrsasign@ca5b027CVE-2026-4598 is a CWE-835 vulnerability in jsrsasign. O3 Security confirms whether CVE-2026-4598 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
jsrsasign is vulnerable to DoS through Infinite Loop when processing zero or negative inputs
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
Versions of the package jsrsasign before 11.1.1 are vulnerable to Infinite loop via the bnModInverse function in ext/jsbn2.js when the BigInteger.modInverse implementation receives zero or negative inputs, allowing an attacker to hang the process permanently by supplying such crafted values (e.g., modInverse(0, m) or modInverse(-1, m)).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | jsrsasign | all versions | 11.1.1 |
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 11.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-4598 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-2026-4598 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-2026-4598. 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-2026-4598 in your dependencies?
O3 detects CVE-2026-4598 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.