CVE-2026-59638

EUVD-2026-52016
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).
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
UNKNOWN
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Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 19%
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Debian Releases
Debian Product
Codename
bouncycastle
bookworm
vulnerable
bullseye
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
Common Weakness Enumeration
Vulnerability Media Exposure
References
https://github.com/bcgit/bc-java/commit/5ac55351cd1a8a7184d41c96a7ee87df0770240a
https://github.com/bcgit/bc-java/commit/799bd15320a6310a447863638aa3df64acef829b
https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059638