CVE-2026-4601

critical

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.

References

https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370941

https://github.com/kjur/jsrsasign/pull/645

https://github.com/kjur/jsrsasign/commit/0710e392ec35de697ce11e4219c988ba2b5fe0eb

https://gist.github.com/Kr0emer/93789fe6efe5519db9692d4ad1dad586

Details

Source: Mitre, NVD

Published: 2026-03-23

Updated: 2026-03-23

Risk Information

CVSS v2

Base Score: 9.4

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

CVSS v4

Base Score: 9.4

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:H/SA:N

Severity: Critical

EPSS

EPSS: 0.00021