# CVE-2026-5588

## Summary

- **CVE ID:** CVE-2026-5588
- **Severity:** MEDIUM
- **CVSS Score:** 7.5 (CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/U:Amber)
- **CWE:** CWE-327, CWE-327
- **Published:** Apr 15, 2026
- **Last Modified:** Sep 18, 2026

## Description

: Use of a Broken or Risky Cryptographic Algorithm vulnerability in Legion of the Bouncy Castle Inc. BC-JAVA bcpkix on all (pkix modules).


PKIX draft CompositeVerifier accepts empty signature sequence as valid.


This issue affects BC-JAVA: from 1.49 before 1.84.

## Affected Products

- Legion of the Bouncy Castle Inc. — BC-JAVA (1.49)
- Legion of the Bouncy Castle Inc. — BC-JAVA (1.67)
- Legion of the Bouncy Castle Inc. — BCPKIX-FIPS (2.0.6)
- Legion of the Bouncy Castle Inc. — BCPKIX-FIPS (2.1.7)
- Legion of the Bouncy Castle Inc. — BCPIX-LTS (2.73.7)
- Legion of the Bouncy Castle Inc. — BC-JAVA (1.81)
- Legion of the Bouncy Castle Inc. — BC-JAVA (1.82)

## References

- [CNA](https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%905588)
- [CNA](https://github.com/bcgit/bc-java/commit/656bae0dbd9b1521f840521ff786e78749fe3057)
- [redhat-SADP](https://access.redhat.com/security/cve/CVE-2026-5588)
- [redhat-SADP](https://bugzilla.redhat.com/show_bug.cgi?id=2458634)
- [redhat-SADP](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5588.json)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18054)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18055)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:14276)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:14272)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:13631)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:18059)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:21772)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:17668)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:11720)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:11721)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:53644)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:53806)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60247)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60239)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60251)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60246)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60250)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60259)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60254)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60249)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60248)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60252)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:60256)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:66488)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:53645)
- [redhat-SADP](https://access.redhat.com/errata/RHSA-2026:53646)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.64%
- **EPSS Percentile:** 49.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._