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High

jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass

  • Disclosed: 23.03.2026
  • Updated: 11.10.2026 10:22

Versions of the package jsrsasign before 11.1.1 are vulnerable to Incorrect Conversion between Numeric Types due to handling negative exponents in ext/jsbn2.js. An attacker can force the computation of incorrect modular inverses and break signature verification by calling modPow with a negative exponent.

Affected software

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PlatformPackageVulnerable versionsFixed in
npm package jsrsasign < 11.1.1 11.1.1

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-681
Platform
npm
Package
jsrsasign
Disclosed
23.03.2026
Updated
11.10.2026 10:22

Sources and licenses

OSV / GitHub Advisory Database - GHSA-8qwj-4jxw-m8jw - CC BY 4.0

Vulnerability history: jsrsasign

All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (14) in the archive
Total entries
14
First → latest
06.2020 03.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 4
  • High 7
  • Medium 2
  • Low 1

Disclosures per year

Severity:
  1. jsrsasign: DSA signatures or X.509 certificates can be forged via DSA domain-parameter validation in KJUR.crypto.DSA.setPublic
    High · 7.4 CVE-2026-4600 < 11.1.1 11.1.1
  2. jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass this entry
    High · 7.5 CVE-2026-4602 < 11.1.1 11.1.1
  3. jsrsasign: Incomplete Comparison Allows DSA Private Key Recovery via Biased Nonce Generation
    Critical · 9.1 CVE-2026-4599 >= 7.0.0, < 11.1.1 11.1.1
  4. jsrsasign is vulnerable to DoS through Infinite Loop when processing zero or negative inputs
    High · 7.5 CVE-2026-4598 < 11.1.1 11.1.1
  5. jsrsasign: Missing cryptographic validation during DSA signing enables private key extraction
    High · 8.7 CVE-2026-4601 < 11.1.1 11.1.1
  6. Marvin Attack of RSA and RSAOAEP decryption in jsrsasign
    High · 7.5 CVE-2024-21484 < 11.0.0 11.0.0
  7. JWS and JWT signature validation vulnerability with special characters
    High · 8.6 CVE-2022-25898 >= 4.8.0, < 10.5.25 10.5.25
  8. RSA signature validation vulnerability on maleable encoded message in jsrsasign
    Critical · 9.1 CVE-2021-30246 < 10.2.0 10.2.0
  9. ECDSA signature validation vulnerability by accepting wrong ASN.1 encoding in jsrsasign
    High · 7.5 CVE-2020-14966 >= 4.0.0, < 8.0.19 8.0.19
  10. RSA PKCS#1 decryption vulnerability with prepending zeros in jsrsasign
    Critical · 9.8 CVE-2020-14967 < 8.0.18 8.0.18
  11. RSA-PSS signature validation vulnerability by prepending zeros in jsrsasign
    Critical · 9.8 CVE-2020-14968 >= 3.0.0, < 8.0.17 8.0.17

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