CVE-2026-4601
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.30%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 8.8 HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:H/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.30% probability · 23th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-325
- Affected
- kjur/jsrsasign
- Source
- report@snyk.io
References
- https://gist.github.com/Kr0emer/93789fe6efe5519db9692d4ad1dad586Exploit, Mitigation, Third Party Advisory
- https://github.com/kjur/jsrsasign/commit/0710e392ec35de697ce11e4219c988ba2b5fe0ebPatch
- https://github.com/kjur/jsrsasign/pull/645Issue Tracking
- https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812269
- https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370941Third Party Advisory
- 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
- https://access.redhat.com/security/cve/CVE-2026-4601
- https://bugzilla.redhat.com/show_bug.cgi?id=2450209
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4601.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.