Vulnerability in Bouncy Castle for Java Affects Multiple Versions
CVE-2026-59641

8.7HIGH

Key Information:

Vendor

Legion Of The Bouncy Castle Inc.

Status
Bc-java
Bc-lts-java
Bc-fja
Vendor
CVE Published:
3 August 2026

What is CVE-2026-59641?

In Bouncy Castle for Java prior to version 1.85, a security misconfiguration allows the S/MIME validator to improperly trust the signer-asserted signingTime during path validation. This can lead to exploitation risks, particularly in environments that rely on S/MIME for secure email communications. The issue is also present in the Bouncy Castle for Java LTS versions before 2.73.12, and specific FIPS-compliant versions before defined patch levels, necessitating immediate review and updates for affected installations.

Affected Version(s)

BC-FJA all 1.0.0 < 1.0.7

BC-FJA all 2.0.0 < 2.0.7

BC-FJA all 2.1.0 < 2.1.7

References

https://github.com/bcgit/bc-java/wiki/CVE-2026-59641
vendor-advisory
https://github.com/bcgit/bc-java/commit/2f81b22d559b3a1b0...
patch
https://github.com/bcgit/bc-java/commit/fd89fe918b37fea1c...
patch

CVSS V4

Score:
8.7
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Alex Gaynor in collaboration with Claude and Anthropic Research
.