Which versions of jsrsasign are affected by CVE-2026-4600?

jsrsasign versions before 11.1.1 contain a cryptographic signature bypass vulnerability that allows attackers to forge DSA signatures and X.509 certificates, directly compromising authentication and…. A patch is available.

How to fix or mitigate CVE-2026-4600?

Within 24 hours: Identify all applications and dependencies using jsrsasign and document current versions in use. Within 7 days: Upgrade jsrsasign to version 11.1.1 or later across all development, staging, and production environments; verify upgrades via dependency audits (npm audit, yarn audit, or equivalent). Within 30 days: Conduct code review of JWT validation and certificate verification implementations to confirm proper use of patched library; perform security regression testing on authentication and signature validation flows.

jsrsasign CVE-2026-4600

Q: What is the CVSS score of CVE-2026-4600?

CVE-2026-4600 has a CVSS 4.0 base score of 8.1 (High). CVSS vector: 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 exploitation probability: 0.0%.

EUVD-2026-14375 HIGH

Improper Verification of Cryptographic Signature (CWE-347)

2026-03-23 snyk

GHSA-wvqx-v3f6-w8rh

Information Disclosure Jwt Attack Jsrsasign

8.1

CVSS 4.0 · Vendor: snyk

Severity by source

Vendor (snyk) PRIMARY

8.1 HIGH

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

Red Hat

8.2 HIGH

qualitative

Primary rating from Vendor (snyk).

CVSS VectorVendor: snyk

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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Apr 29, 2026 - 01:34 vuln.today

v2 (cvss_changed)

Re-analysis Queued

Apr 29, 2026 - 01:11 vuln.today

cvss_changed

CVSS changed

Apr 29, 2026 - 01:11 NVD

7.4 (HIGH) 8.1 (HIGH)

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

EUVD ID Assigned

Mar 23, 2026 - 05:45 euvd

EUVD-2026-14375

Analysis Generated

Mar 23, 2026 - 05:45 vuln.today

CVE Published

Mar 23, 2026 - 05:00 nvd

HIGH 7.4

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

34 npm packages depend on jsrsasign (9 direct, 25 indirect)

Ecosystem-wide dependent count for version 11.1.1.

DescriptionCVE.org

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.

AnalysisAI

Cryptographic signature bypass in jsrsasign before 11.1.1 allows remote attackers to forge DSA signatures and X.509 certificates by supplying malicious domain parameters (g=1, y=1, r=1) that cause verification functions to incorrectly validate any message hash. This actively undermines authentication and integrity checks in applications using the library for JWT validation, certificate verification, or digital signatures. EPSS score is negligible (0.01%) despite proof-of-concept availability, and CISA SSVC classifies this as requiring proof-of-concept but not automatable, indicating targeted exploitation risk rather than widespread scanning.

Technical ContextAI

jsrsasign is a pure JavaScript cryptographic library implementing RSA, ECDSA, DSA signature schemes and X.509 certificate handling, commonly used in Node.js and browser environments for JWT token validation and PKI operations. The vulnerability (CWE-347: Improper Verification of Cryptographic Signature) exists in the DSA domain-parameter validation logic within KJUR.crypto.DSA.setPublic and related verification flows in src/dsa-2.0.js. DSA signature verification requires validating that domain parameters (p, q, g) and public key (y) satisfy mathematical properties - specifically that g generates a subgroup of order q. By accepting attacker-controlled parameters where g=1 and y=1, the verification equation (v = r) becomes trivially true when the attacker sets r=1, regardless of the message hash or actual signature value s. This bypasses the fundamental cryptographic assurance that only the holder of the private key can produce valid signatures.

RemediationAI

Upgrade jsrsasign to version 11.1.1 or later, which implements proper DSA domain-parameter validation per the fix in GitHub commit 37b4c06b145c7bfd6bc2a6df5d0a12c56b15ef60 and pull request #646 (https://github.com/kjur/jsrsasign/pull/646). Red Hat users should apply patches per their respective RHSA advisories. If immediate upgrade is not feasible, implement these compensating controls with noted trade-offs: (1) Disable DSA algorithm support in signature verification code and reject any certificates or tokens using DSA signatures - this breaks legitimate DSA-signed content but RSA and ECDSA remain functional; (2) Implement strict allowlisting of trusted certificate authorities and reject any certificates with unexpected issuers - reduces attack surface but requires maintaining CA lists and breaks dynamic trust scenarios; (3) Add pre-verification checks to reject DSA public keys where g=1 or y=1 before calling jsrsasign verification functions - requires modifying application code and understanding DSA parameter constraints. Do not rely solely on updating cryptographic libraries in transitive dependencies; verify that your application code and direct dependencies have also upgraded. Test thoroughly as cryptographic library updates can expose previously-masked implementation bugs in consuming applications.