CVE-2026-59639

CMS verifySignatures returns true for SignedData with zero signers

State: Published
Severity: 8.7 High
Published: Aug 3, 2026
Updated: Aug 3, 2026
Reserved: Jul 6, 2026

Description

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).

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/U:Amber	bcorg

Weaknesses

CWE-347 Improper Verification of Cryptographic Signature

Affected Products

Product	Versions
BC-JAVALegion of the Bouncy Castle Inc.	before 1.85Affected
BC-LTS-JAVALegion of the Bouncy Castle Inc.	2.73.0 to before 2.73.12Affected
BC-FJALegion of the Bouncy Castle Inc.	1.0.0 to before 1.0.12Affected 2.0.0 to before 2.0.12Affected 2.1.0 to before 2.1.12Affected

References

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