---
id: CVE-2026-4602
title: >-
  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
summary: >-
  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 brea…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-681
vendor: kjur
product: jsrsasign
affected:
  - jsrsasign < 11.1.1
patched:
  - jsrsasign 11.1.1
published: '2026-03-23'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T13:20:22.877'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4602'
references:
  - url: 'https://gist.github.com/Kr0emer/7ecd2be7d17419e4677315ef3758faf5'
    label: report@snyk.io
  - url: >-
      https://github.com/kjur/jsrsasign/commit/5ea1c32bb2aa894b4bd29849839afe4f98728195
    label: report@snyk.io
  - url: 'https://github.com/kjur/jsrsasign/pull/650'
    label: report@snyk.io
  - url: 'https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812274'
    label: report@snyk.io
  - url: 'https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371175'
    label: report@snyk.io
  - url: 'https://access.redhat.com/errata/RHSA-2026:19375'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19409'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:19410'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:6568'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:6720'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:6912'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:6926'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-4602'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2450206'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4602.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-4602'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-4602'
tags:
  - nvd
  - cve.org
  - exploit-available
  - csaf
  - vex
  - red-hat
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-03-23T14:37:35.060950Z'
epss: 0.0049
epssPercentile: 0.41251
ingestedAt: '2026-06-29T13:24:34.812Z'
---

## Overview

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

- `jsrsasign < 11.1.1`

## Remediation

Upgrade past the affected range:

- `jsrsasign 11.1.1`

## Vendor advisories

- **RHSA-2026:19409** · Red Hat · fixed in: Migration Toolkit for Virtualization 2.1 · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19409)
- **RHSA-2026:19410** · Red Hat · fixed in: Migration Toolkit for Virtualization 2.9 · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19410)
- **RHSA-2026:6912** · Red Hat · fixed in: Red Hat Quay 3.10 · released 2026-04-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:6912)
- **RHSA-2026:6720** · Red Hat · fixed in: Red Hat Quay 3.12 · released 2026-04-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:6720)
- **RHSA-2026:6568** · Red Hat · fixed in: Red Hat Quay 3.15 · released 2026-04-03 · [advisory](https://access.redhat.com/errata/RHSA-2026:6568)
- **RHSA-2026:19375** · Red Hat · fixed in: Red Hat Quay 3.16 · released 2026-05-19 · [advisory](https://access.redhat.com/errata/RHSA-2026:19375)
- **RHSA-2026:6926** · Red Hat · fixed in: Red Hat Quay 3.9 · released 2026-04-07 · [advisory](https://access.redhat.com/errata/RHSA-2026:6926)