jsrsasign: Negative Exponent Handling Leads to Signature Verification Bypass
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.
This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. Rated impact: confidentiality none, integrity none, availability high.
The score comes from this 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
CVE-2026-4602 is classified as CWE-681: Incorrect Conversion between Numeric Types. When converting from one data type to another, such as long to integer, data can be omitted or translated in a way that produces unexpected values. If the resulting values are used in a sensitive context, then dangerous behaviors may occur.
CVE-2026-4602 is recorded against 1 package.
Published on 23 March 2026 and last revised on 17 August 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from OSV.
nvd.nist.gov (Advisory)
github.com (Web)
github.com (Web)
security.snyk.io (Web)
security.snyk.io (Web)
security.access.redhat.com (Web)
github.com (Package)
gist.github.com (Web)
bugzilla.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
access.redhat.com (Web)
jsrsasign has other advisories on record. If you are patching this one, these are worth checking on the same host:
These advisories are the same class of weakness (CWE-681: Incorrect Conversion between Numeric Types) in other software:
Details
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
Affected Packages
| Software | From version | Fixed in |
|---|---|---|
| jsrsasign | — | — |
References
Similar Threats
Exploit Protection
CVE-2026-4602 carries CVSS 8.0 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.
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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.
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