CVE-2026-59639

In Bouncy Castle for Java before 1.85, CMS verifySignatures returns true for SignedData with zero signers. This issue also affects Bouncy Castle for Java LTS before 2.73.12, and Bouncy Castle for Java FIPS (BC-FJA) before bcpkix-fips 1.0.12 (1.0.X series), 2.0.12 (2.0.X series) and 2.1.12 (2.1.X series).

Weakness

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/463.html
• https://cwe.mitre.org/data/definitions/475.html

References

• https://github.com/bcgit/bc-java/commit/99ddc6dcc6782e6a76b0dd587c77e62eb7096ad0
• https://github.com/bcgit/bc-java/wiki/CVE%E2%80%902026%E2%80%9059639