Bug 2510201 (CVE-2026-59638) - CVE-2026-59638 org.bouncycastle/bctls-jdk15on: org.bouncycastle/bctls-fips: Bouncy Castle for Java: Improper hostname validation due to default CN-fallback in JSSE verifier
Summary: CVE-2026-59638 org.bouncycastle/bctls-jdk15on: org.bouncycastle/bctls-fips: B...
Keywords:
Status: NEW
Alias: CVE-2026-59638
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2533156 2533157
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-03 02:01 UTC by OSIDB Bzimport
Modified: 2026-09-14 15:52 UTC (History)
114 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)

Description OSIDB Bzimport 2026-08-03 02:01:55 UTC 
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).
Note You need to log in before you can comment on or make changes to this bug.