# CVE-2026-4602

## Summary

- **CVE ID:** CVE-2026-4602
- **Severity:** HIGH
- **CVSS Score:** 8.7 (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
- **Published:** Mar 23, 2026
- **Last Modified:** Sep 7, 2026

## 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.

## Affected Products

- n/a — jsrsasign (0)
- n/a — org.webjars.npm:jsrsasign (0)

## References

- [CNA](https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-15371175)
- [CNA](https://gist.github.com/Kr0emer/7ecd2be7d17419e4677315ef3758faf5)
- [CNA](https://github.com/kjur/jsrsasign/pull/650)
- [CNA](https://github.com/kjur/jsrsasign/commit/5ea1c32bb2aa894b4bd29849839afe4f98728195)
- [CNA](https://security.snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-15812274)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-4602)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2450206)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4602.json)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19409)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19410)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:6720)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:6568)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:19375)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:6912)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:6926)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.49%
- **EPSS Percentile:** 40.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._