SEPTEMBER 19, 2026
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Case File

CVE-2026-59638

MEDIUM · CVSS 6.5 EPSS 0.21% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-03 · Last synced 2026-09-02

CyberRota Analysis

AI-Generated

Bouncy Castle for Java versions prior to 1.85, along with specific LTS and FIPS versions, have a vulnerability where the JSSE hostname verifier's CN-fallback feature is enabled by default, contrary to the intended opt-in configuration. This misconfiguration could potentially allow attackers to bypass hostname verification, leading to man-in-the-middle attacks. Organizations using affected versions of Bouncy Castle should prioritize remediation to ensure secure hostname verification practices are enforced.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-59638
Severity
MEDIUM
CVSS
6.5
EPSS
0.21%
Java

Original NVD Description

In Bouncy Castle for Java before 1.85, JSSE hostname verifier CN-fallback enabled by default despite documented opt-in. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bctls-fips 1.0.24 (1.0.X series), 2.0.24 (2.0.X series) and 2.1.24 (2.1.X series).

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