What’s Vulnerable › Vulnerabilities

CVE-2026-4601

• Severity: critical (CVSS 9.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-23 · updated 2026-09-10
• Weakness: CWE-325

Description

Versions of the package jsrsasign before 11.1.1 are vulnerable to Missing Cryptographic Step via the KJUR.crypto.DSA.signWithMessageHash process in the DSA signing implementation. An attacker can recover the private key by forcing r or s to be zero, so the library emits an invalid signature without retrying, and then solves for x from the resulting signature.

Affected products

• jsrsasign: before 11.1.1 — fixed in 11.1.1

How to fix

Upgrade to a fixed version: jsrsasign 11.1.1. Check the vendor advisory for mitigations.

References

• https://gist.github.com/Kr0emer/93789fe6efe5519db9692d4ad1dad586
• https://github.com/kjur/jsrsasign/commit/0710e392ec35de697ce11e4219c988ba2b5fe0eb
• https://github.com/kjur/jsrsasign/pull/645
• https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812269
• https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370941
• https://access.redhat.com/errata/RHSA-2026:19375
• https://access.redhat.com/errata/RHSA-2026:19409
• https://access.redhat.com/errata/RHSA-2026:19410
• https://access.redhat.com/errata/RHSA-2026:6568
• https://access.redhat.com/errata/RHSA-2026:6720
• https://access.redhat.com/errata/RHSA-2026:6912
• https://access.redhat.com/errata/RHSA-2026:6926

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