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).
History

Fri, 28 Aug 2026 17:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'}

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N'}


Fri, 28 Aug 2026 15:15:00 +0000

Type Values Removed Values Added
First Time appeared Bouncycastle
Bouncycastle bc-java
Bouncycastle bctls-fips
Bouncycastle bouncy Castle For Java Lts
CPEs cpe:2.3:a:bouncycastle:bc-java:*:*:*:*:*:*:*:*
cpe:2.3:a:bouncycastle:bctls-fips:*:*:*:*:*:*:*:*
cpe:2.3:a:bouncycastle:bouncy_castle_for_java_lts:*:*:*:*:*:*:*:*
Vendors & Products Bouncycastle
Bouncycastle bc-java
Bouncycastle bctls-fips
Bouncycastle bouncy Castle For Java Lts
Metrics cvssV3_1

{'score': 8.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'}


Mon, 03 Aug 2026 16:15:00 +0000

Type Values Removed Values Added
First Time appeared Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-fja
Legion Of The Bouncy Castle Inc. bc-java
Legion Of The Bouncy Castle Inc. bc-lts-java
Vendors & Products Legion Of The Bouncy Castle Inc.
Legion Of The Bouncy Castle Inc. bc-fja
Legion Of The Bouncy Castle Inc. bc-java
Legion Of The Bouncy Castle Inc. bc-lts-java

Mon, 03 Aug 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Mon, 03 Aug 2026 05:30:00 +0000


Mon, 03 Aug 2026 01:15:00 +0000

Type Values Removed Values Added
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).
Title JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
Weaknesses CWE-297
References
Metrics cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber'}


cve-icon MITRE

Status: PUBLISHED

Assigner: bcorg

Published: 2026-08-03T00:57:31.904Z

Updated: 2026-08-03T13:23:06.454Z

Reserved: 2026-07-06T06:58:29.263Z

Link: CVE-2026-59638

cve-icon Vulnrichment

Updated: 2026-08-03T13:23:02.399Z

cve-icon NVD

Status : Analyzed

Published: 2026-08-03T01:16:43.543

Modified: 2026-08-28T17:29:17.083

Link: CVE-2026-59638

cve-icon Redhat

No data.