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
kjur: jsrsasign
References10
- github.com/kjur/jsrsasign/commit/0710e392ec35de697ce11e4219c988… Patch
- gist.github.com/Kr0emer/93789fe6efe5519db9692d4ad1dad586 ExploitMitigationThird Party Advisory
- github.com/kjur/jsrsasign/pull/645 Issue Tracking
- security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812269
- security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370941 Third Party Advisory
- access.redhat.com/errata/RHSA-2026:19375
- access.redhat.com/errata/RHSA-2026:19409
- access.redhat.com/errata/RHSA-2026:19410
- access.redhat.com/errata/RHSA-2026:6568
- access.redhat.com/errata/RHSA-2026:6720
Metrics
- CVSS 3.1
-
9.1
CRITICAL
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - CVSS 4.0
-
8.8
HIGH
Score source: CNA
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/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 24 · as of 12 November 2026
- CWE
- CWE-325
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.