CVE-2026-59638

critical

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).

References

https://github.com/bcgit/bc-java/wiki/CVE-2026-59638

https://github.com/bcgit/bc-java/commit/799bd15320a6310a447863638aa3df64acef829b

https://github.com/bcgit/bc-java/commit/5ac55351cd1a8a7184d41c96a7ee87df0770240a

Details

Source: Mitre, NVD

Published: 2026-08-03

Updated: 2026-08-03

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.1

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Severity: Critical

CVSS v4

Base 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

Severity: Critical