CVE-2026-4602

jsrsasign: jsrsasign: Signature verification bypass via negative exponent handling

Published Mar 23, 2026 CVSS 4.0 · 8.7 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

Advisories

Source ID Title
Github GHSA Github GHSA GHSA-8qwj-4jxw-m8jw jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass
History
Type Values Removed Values Added
First Time appeared Jsrsasign Project
Jsrsasign Project jsrsasign
CPEs cpe:2.3:a:jsrsasign_project:jsrsasign:*:*:*:*:*:node.js:*:*
Vendors & Products Jsrsasign Project
Jsrsasign Project jsrsasign
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Title jsrsasign: jsrsasign: Signature verification bypass via negative exponent handling
References
Metrics threat_severity

None

threat_severity

Important

Type Values Removed Values Added
First Time appeared Kjur
Kjur jsrsasign
Vendors & Products Kjur
Kjur jsrsasign
Type Values Removed Values Added
Description 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.
Weaknesses CWE-681
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P'}

cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
snyk
Published
Updated
Sep 10, 2026, 12:04 PM
Reserved
Mar 22, 2026, 4:26 PM
Status
Modified
Published
Mar 23, 2026, 6:16 AM
Modified
Sep 10, 2026, 1:20 PM
Severity
Important
Public date
Mar 23, 2026, 5:00 AM