Which versions of jsrsasign are affected by CVE-2026-4601?

jsrsasign library versions before 11.1.1 allow attackers to recover RSA/DSA private keys through forced invalid signature exploitation, directly compromising cryptographic authentication and data…. A patch is available.

How to fix or mitigate CVE-2026-4601?

Within 24 hours: Identify all systems and applications using jsrsasign and document current versions via dependency scanning. Within 7 days: Upgrade jsrsasign to version 11.1.1 or later on all affected systems and redeploy applications. Within 30 days: Rotate all private keys generated or used with jsrsasign versions prior to 11.1.1, audit key usage logs for suspicious signing patterns, and validate patch deployment across all environments.

jsrsasign CVE-2026-4601

Q: What is the CVSS score of CVE-2026-4601?

CVE-2026-4601 has a CVSS 4.0 base score of 8.8 (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: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 exploitation probability: 0.0%.

EUVD-2026-14377 HIGH

Missing Cryptographic Step (CWE-325)

2026-03-23 snyk

GHSA-w8q8-93cx-6h7r

Information Disclosure Jsrsasign

8.8

CVSS 4.0 · Vendor: snyk

Severity by source

Vendor (snyk) PRIMARY

8.8 HIGH

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

Red Hat

8.7 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: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

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Updated

Apr 29, 2026 - 01:33 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

8.7 (HIGH) 8.8 (HIGH)

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

EUVD ID Assigned

Mar 23, 2026 - 05:45 euvd

EUVD-2026-14377

Analysis Generated

Mar 23, 2026 - 05:45 vuln.today

CVE Published

Mar 23, 2026 - 05:00 nvd

HIGH 8.7

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 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.

AnalysisAI

Private key recovery is possible in jsrsasign versions before 11.1.1 when attackers force invalid DSA signatures with zero r or s values during the signing process. The library fails to validate or retry these malformed signatures, allowing attackers to algebraically solve for the private key x from the emitted signature. Publicly available exploit code exists demonstrating the key recovery technique (EPSS: 0.02%, percentile 5%), though no confirmed active exploitation. Vendor-released patch: version 11.1.1.

Technical ContextAI

jsrsasign is a pure JavaScript cryptographic library implementing RSA, ECC, and DSA signing algorithms. The vulnerability affects the KJUR.crypto.DSA.signWithMessageHash function in the DSA (Digital Signature Algorithm) implementation, classified as CWE-325 (Missing Cryptographic Step). DSA signatures consist of two components (r, s) derived from a random nonce k and the private key x. Proper DSA implementations must validate that neither r nor s equals zero, as this mathematical edge case allows trivial private key extraction. The affected library (CPE: cpe:2.3:a:n/a:jsrsasign:*:*:*:*:*:*:*:*) lacks this critical validation step, emitting invalid signatures without retrying with a new nonce. An attacker who can observe or influence the signing process can force these zero-value conditions and then algebraically derive the private key from the invalid signature parameters.

RemediationAI

Upgrade jsrsasign to version 11.1.1 or later, which implements proper validation to reject signatures with r=0 or s=0 and retry with a new nonce as confirmed in GitHub commit 0710e392ec35de697ce11e4219c988ba2b5fe0eb and pull request 645 (https://github.com/kjur/jsrsasign/pull/645). For Node.js projects, update package.json to specify jsrsasign version >=11.1.1 and run npm update or yarn upgrade. Red Hat customers should apply platform-specific patches per advisories at https://access.redhat.com/errata/RHSA-2026:6912 and related RHSA bulletins. If immediate patching is not feasible, implement compensating controls: (1) Migrate DSA signing operations to ECDSA or RSA-PSS algorithms which are not affected by this specific flaw (trade-off: requires certificate reissuance and client compatibility verification), (2) Implement application-layer signature validation that rejects signatures where r=0 or s=0 before accepting them (trade-off: adds processing overhead and may break legitimate but rare edge cases), (3) Restrict signing operations to trusted internal services only, removing network accessibility (trade-off: limits architectural flexibility for distributed systems). Note that verification-only usage of jsrsasign does not expose the private key recovery vector.