Vulnerability Description
Versions of the package jsrsasign before 11.1.1 are vulnerable to Division by zero due to the RSASetPublic/KEYUTIL parsing path in ext/rsa.js and the BigInteger.modPowInt reduction logic in ext/jsbn.js. An attacker can force RSA public-key operations (e.g., verify and encryption) to collapse to deterministic zero outputs and hide “invalid key” errors by supplying a JWK whose modulus decodes to zero.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Jsrsasign Project | Jsrsasign | < 11.1.1 |
Related Weaknesses (CWE)
References
- https://gist.github.com/Kr0emer/5366b7364c4fbf7e754bc377f321e9f3ExploitMitigationThird Party Advisory
- https://github.com/kjur/jsrsasign/commit/dc41d49fac4297e7a737a3ef8ebd0aa9c49ef93Patch
- https://github.com/kjur/jsrsasign/pull/649Issue Tracking
- https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371176Third Party Advisory
FAQ
What is CVE-2026-4603?
CVE-2026-4603 is a vulnerability with a CVSS score of 5.9 (MEDIUM). Versions of the package jsrsasign before 11.1.1 are vulnerable to Division by zero due to the RSASetPublic/KEYUTIL parsing path in ext/rsa.js and the BigInteger.modPowInt reduction logic in ext/jsbn.j...
How severe is CVE-2026-4603?
CVE-2026-4603 has been rated MEDIUM with a CVSS base score of 5.9/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4603?
Check the references section above for vendor advisories and patch information. Affected products include: Jsrsasign Project Jsrsasign.