9.1

CVE-2026-4600: kjur jsrsasign

CVSS: 9.1v4.0CriticalModified
AliasesGHSA-wvqx-v3f6-w8rh
Published 23-03-2026Last modified 10-09-2026
Open JSON

Vulnerability summary

CVE-2026-4600 is a critical (CVSS 9.1) vulnerability in kjur jsrsasign. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 25.1% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.1/10
010
Critical · v4.0 (CVE.org)
EPSS score
0.33%
0%100%
Low · +0.11 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github

Timeline

  1. 23-03-2026
    PublishedVulnerability first disclosed.
  2. 10-09-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 3 sources · 2 versions

EPSS trend

Probability

0.33%

Chance of exploitation in the next 30 days

Percentile

25%

Versus all other CVEs

30-day change

+0.11 pp

From 0.22% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.33%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • githubUnverified

    Bf15Ddc097176E951659A24A8E9002A7

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Kjur1 product
Npm1 product
  • jsrsasign< 11.1.1

2 vendors · 2 products

References

17 links
Show all 17 references