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CVE

CVE-2026-59638

JSSE hostname verifier CN-fallback enabled by default despite documented opt-in
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CVE

CVE-2026-59638

JSSE hostname verifier CN-fallback enabled by default despite documented opt-in

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).

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
9.3
-
4.0
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
C
H
U
0
-
C
H
U
-

Related Resources

No items found.

References

https://www.bouncycastle.org/download/bouncy-castle-java-fips/, https://www.bouncycastle.org/download/bouncy-castle-java-lts/, https://www.bouncycastle.org/download/bouncy-castle-java/, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59638.json, https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059638, https://nvd.nist.gov/vuln/detail/CVE-2026-59638, https://github.com/bcgit/bc-java/commit/5ac55351cd1a8a7184d41c96a7ee87df0770240a, https://github.com/bcgit/bc-java/commit/799bd15320a6310a447863638aa3df64acef829b, https://github.com/bcgit/bc-java, https://github.com/bcgit/bc-lts-java

Severity

0

CVSS Score
0
10

Basic Information

Base CVSS
0
EPSS Probability
0.0021%
EPSS Percentile
0.11368%
Introduced Version
0f1260dc7e3c42be130c45fdad5b4363170ddf32,468b5082f3f0971e80bf9edb7029c17b39b9ba0c,0
Fix Available
57fbd3c501f7a369f64eda311d6a709fc0bcae84,f101b232c5d3e07ecdd504210a57e43831d6cd65

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