CVE-2026-4600: Kjur Jsrsasign

Critical severity, CVSS 9.1. EPSS: 0.3% chance of exploitation in the next 30 days.

Versions of the package jsrsasign before 11.1.1 are vulnerable to Improper Verification of Cryptographic Signature via the DSA domain-parameter validation in KJUR.crypto.DSA.setPublic (and the related DSA/X509 verification flow in src/dsa-2.0.js). An attacker can forge DSA signatures or X.509 certificates that X509.verifySignature() accepts by supplying malicious domain parameters such as g=1, y=1, and a fixed r=1, which make the verification equation true for any hash.

Affected products

• Kjur Jsrsasign: before 11.1.1 (fixed in 11.1.1)

Published 2026-03-23. Last modified 2026-09-10.