Skip to main content

Boteraser | Website and Server Security Solutions

🛡️ CVE-2026-4602 — jsrsasign

🟠 CVSS 8.0 — High ⚠️ Exploit Public CWE-681 OSV
8.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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.

How this vulnerability can be exploited

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.

CVSS metrics in full

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

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Attack requirements: None — no deployment-specific condition has to hold.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Confidentiality impact: None.
  • Integrity impact: None.
  • Availability impact: High — total loss, or loss the attacker controls.

Weakness class

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.

Affected software

CVE-2026-4602 is recorded against 1 package.

  • jsrsasign

Timeline and source

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.

References

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)

Other advisories for this package

jsrsasign has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-681: Incorrect Conversion between Numeric Types) in other software:

Details

Severity HIGH
CVSS Score 8.0
CVSS 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
CWE CWE-681
Public Exploit ⚠️ Yes
Source OSV
Published 2026-03-23
Updated 2026-08-20
Modified 2026-08-17

Affected Packages

Software From version Fixed in
jsrsasign

References

Similar Threats

Exploit Protection

Are you running jsrsasign?

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.

Check My Site For CVE-2026-4602 →

No credit card required  ·  Results in minutes

ⓘ 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.

Browse related advisories

All advisoriesCVECVE 2026