Which versions of Jsrsasign are affected by CVE-2026-4599?

A critical vulnerability in the jsrsasign cryptographic library (CVE-2026-4599, CVSS 9.1) enables attackers to extract private DSA keys remotely without authentication.. A patch is available.

How to fix or mitigate CVE-2026-4599?

Within 24 hours: Identify all internal and third-party applications using jsrsasign library versions 7.0.0-11.1.0; audit systems for DSA key usage; escalate findings to application owners. Within 7 days: Evaluate alternative cryptographic libraries (e.g., TweetNaCl.js, libsodium.js); begin migration planning; implement network monitoring for exploitation attempts. Within 30 days: Complete migration to patched or alternative library; regenerate all DSA keys used by affected systems; validate cryptographic operations in production.

Jsrsasign CVE-2026-4599

Q: What is the CVSS score of CVE-2026-4599?

CVE-2026-4599 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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-2026-14373 CRITICAL

Incomplete Comparison with Missing Factors (CWE-1023)

2026-03-23 snyk

GHSA-5jx8-q4cp-rhh6

Information Disclosure Jsrsasign

9.3

CVSS 4.0 · Vendor: snyk

Severity by source

Vendor (snyk) PRIMARY

9.3 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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

9.1 HIGH

qualitative

Primary rating from Vendor (snyk).

CVSS VectorVendor: snyk

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/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

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Re-analysis Queued

Jun 22, 2026 - 03:22 vuln.today

cvss_changed

CVSS changed

Jun 22, 2026 - 03:22 NVD

9.1 (CRITICAL) 9.3 (CRITICAL)

Patch released

Mar 31, 2026 - 21:13 nvd

Patch available

EUVD ID Assigned

Mar 23, 2026 - 05:45 euvd

EUVD-2026-14373

Analysis Generated

Mar 23, 2026 - 05:45 vuln.today

CVE Published

Mar 23, 2026 - 05:00 nvd

CRITICAL 9.1

DescriptionCVE.org

Versions of the package jsrsasign from 7.0.0 and before 11.1.1 are vulnerable to Incomplete Comparison with Missing Factors via the getRandomBigIntegerZeroToMax and getRandomBigIntegerMinToMax functions in src/crypto-1.1.js; an attacker can recover the private key by exploiting the incorrect compareTo checks that accept out-of-range candidates and thus bias DSA nonces during signature generation.

AnalysisAI

The jsrsasign JavaScript cryptographic library contains a critical vulnerability in its random number generation functions that allows attackers to recover private DSA keys through nonce bias exploitation. Versions 7.0.0 through 11.1.0 are affected. A proof-of-concept is publicly available (referenced in GitHub Gist), demonstrating the attack feasibility, and the vulnerability requires no authentication or user interaction for remote exploitation.

Technical ContextAI

jsrsasign is a widely-used pure JavaScript implementation of cryptographic operations including RSA, DSA, ECC, and X.509 certificates, commonly deployed in Node.js applications and browser-based cryptography. The vulnerability stems from CWE-1023 (Incomplete Comparison with Missing Factors) in the getRandomBigIntegerZeroToMax and getRandomBigIntegerMinToMax functions within src/crypto-1.1.js. These functions incorrectly validate randomly generated numbers through flawed compareTo checks, allowing out-of-range values to be accepted as valid candidates. When used for DSA signature generation, this flaw creates a measurable bias in the nonce values, which can be exploited through mathematical analysis of multiple signatures to extract the private signing key, fundamentally breaking the security guarantees of DSA.

RemediationAI

Immediately upgrade jsrsasign to version 11.1.1 or later, which addresses the flawed random number generation logic through the fix implemented in GitHub pull request 647 (https://github.com/kjur/jsrsasign/pull/647) and committed as ee4b013478366cb16cea9a4bdfb218b6077f83b1 (https://github.com/kjur/jsrsasign/commit/ee4b013478366cb16cea9a4bdfb218b6077f83b1). Review the Snyk advisory at https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15370939 for additional guidance. Organizations unable to immediately upgrade should rotate all DSA keys that were generated or used with affected versions, as previously generated signatures may have already leaked information about the private key. Consider migrating from DSA to more modern signature algorithms like ECDSA or EdDSA where feasible, as DSA is increasingly deprecated in favor of more robust alternatives.