Description
Versions of the package jsrsasign before 11.1.1 are vulnerable to Improper Verification of Cryptographic Signature via the DSA domain-parameter validation in KJUR.crypto.DSA.setPublic (and the related DSA/X509 verification flow in src/dsa-2.0.js). An attacker can forge DSA signatures or X.509 certificates that X509.verifySignature() accepts by supplying malicious domain parameters such as g=1, y=1, and a fixed r=1, which make the verification equation true for any hash.
Affected products
kjur: jsrsasign
References10
- github.com/kjur/jsrsasign/commit/37b4c06b145c7bfd6bc2a6df5d0a12… Patch
- gist.github.com/Kr0emer/bf15ddc097176e951659a24a8e9002a7 ExploitMitigationThird Party Advisory
- gist.github.com/Kr0emer/bf15ddc097176e951659a24a8e9002a7 ExploitMitigationThird Party Advisory
- github.com/kjur/jsrsasign/pull/646 Issue Tracking
- security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812268
- security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370940 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
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
-
8.1
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:N/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: 30 · as of 12 November 2026
- CWE
- CWE-347
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.