PT-2026-27057 · Jsrsasign · Jsrsasign

Kr0Emer · Published 2026-03-23 · Updated 2026-03-23 · CVE-2026-4601

NVD

CVSS v3.1

9.1

Critical

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

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.

Exploit

Fix

Weakness Enumeration

CWE-325

Related Identifiers

CVE-2026-4601

Affected Products

Jsrsasign

References · 9

• 🔥 https://gist.github.com/Kr0emer/93789fe6efe5519db9692d4ad1dad586 · Exploit
• https://github.com/kjur/jsrsasign/commit/0710e392ec35de697ce11e4219c988ba2b5fe0eb · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-4601 · Security Note
• https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370941 · Note
• https://twitter.com/TheHackerWire/status/2035964192352837758 · Twitter Post
• https://github.com/kjur/jsrsasign/pull/645 · Note
• https://twitter.com/CVEnew/status/2035992476595408938 · Twitter Post
• https://twitter.com/CveFindCom/status/2035970506520674379 · Twitter Post
• https://twitter.com/VulmonFeeds/status/2035976027483124216 · Twitter Post