CVE-2026-4601

jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction

9.4 CriticalFix available

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: High
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: None

Exploit likelihood

0.30%Up 0.3 points since Mar 23, 2026

What each source reports

CVE List Score used 9.4

Record: CVE-2026-4601
CVSS 4.0: 9.4 CriticalCVSS: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
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N/E:P
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-325, CWE-325
Updated: 2026-11-02

EUVDEUVD-2026-14377 9.4

Record: EUVD-2026-14377
CVSS 4.0: 9.4 CriticalCVSS: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
Updated: 2026-11-02

GitHub AdvisoriesGHSA-w8q8-93cx-6h7r 8.8

jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction

Record: GHSA-w8q8-93cx-6h7r
CVSS 4.0: 8.8 HighCVSS: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
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-325
Updated: 2026-11-02

NVD 8.8

Record: CVE-2026-4601
CVSS 4.0: 8.8 HighCVSS: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
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
CVSS 3.1: 9.1 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-325
Updated: 2026-11-02

OSV 8.8

Record: CVE-2026-4601
CVSS 4.0: 8.8 HighCVSS: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
Weakness: CWE-325
Updated: 2026-11-02

OSVGHSA-w8q8-93cx-6h7r 8.8

jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction

Record: GHSA-w8q8-93cx-6h7r
CVSS 4.0: 8.8 HighCVSS: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
CVSS 3.1: 8.7 HighCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Weakness: CWE-325
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`jsrsasign` npm	before 11.1.1	11.1.1

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-4601 is a critical vulnerability (CVSS 9.4) in Kjur Jsrsasign, published March 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. Fixed in jsrsasign 11.1.1.

References

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