CVE-2026-59638

published 2026-08-03

CVE-2026-59638: 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…

Priority P3 35 medium 6.5 CVSS 3.1

AV N AC L PR N UI N S U C L I L A N

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).

Affected

10 ranges

Vendor	Product	Version range	Fixed in
bouncycastle	bc-java	< 1.85	1.85
bouncycastle	bctls-fips	>= 1.0.0 < 1.0.24	1.0.24
bouncycastle	bctls-fips	>= 2.0.19 < 2.0.24	2.0.24
bouncycastle	bctls-fips	>= 2.1.20 < 2.1.24	2.1.24
bouncycastle	bouncy_castle_for_java_lts	<= 2.73.11	—
legion_of_the_bouncy_castle_inc	bc-fja	>= 1.0.7 < 1.0.24	1.0.24
legion_of_the_bouncy_castle_inc	bc-fja	>= 2.0.0 < 2.0.24	2.0.24
legion_of_the_bouncy_castle_inc	bc-fja	>= 2.1.0 < 2.1.24	2.1.24
legion_of_the_bouncy_castle_inc	bc-java	>= 1.61 < 1.85	1.85
legion_of_the_bouncy_castle_inc	bc-lts-java	>= 2.73.0 < 2.73.12	2.73.12

CVSS provenance

nvd v3.1 6.5 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

nvd v4.0 9.3 CRITICAL 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Amber

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CWE-297