CVE-2026-59639

UNKNOWN 0.0

CMS verifySignatures returns true for SignedData with zero signers

CVSS Score

0.0

EPSS Score

0.0%

EPSS Percentile

0th

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).

CWE	CWE-347
Vendor	legion of the bouncy castle inc.
Product	bc-java
Published	Aug 3, 2026

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Affected Versions

Legion of the Bouncy Castle Inc. / BC-JAVA

0 < 1.85

Legion of the Bouncy Castle Inc. / BC-LTS-JAVA

2.73.0 < 2.73.12

Legion of the Bouncy Castle Inc. / BC-FJA

1.0.0 < 1.0.12 2.0.0 < 2.0.12 2.1.0 < 2.1.12

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/bcgit/bc-java/wiki/CVE-2026-59639 github.com: https://github.com/bcgit/bc-java/commit/99ddc6dcc6782e6a76b0dd587c77e62eb7096ad0

Credits

🔍 Alex Gaynor in collaboration with Claude and Anthropic Research