CVE-2026-59642

A flaw was found in Bouncy Castle for Java. This vulnerability allows a remote attacker to bypass cryptographic integrity checks in the Cryptographic Message Syntax (CMS) AuthenticatedData content without requiring user interaction or elevated privileges. Specifically, when authentication attributes (authAttrs) are present, the content is not properly bound to the Message Authentication Code (MAC). This could lead to a high impact on data integrity, where an attacker might be able to alter authenticated data without detection.

Bouncy Castle for Java is bundled as a cryptographic provider by numerous Red Hat products. When CMS AuthenticatedData is processed with authentication attributes (authAttrs) present, the content is not cryptographically bound to the MAC, allowing an attacker to alter authenticated data without detection. Exploitation requires an application to process attacker-controlled CMS AuthenticatedData using the affected Bouncy Castle APIs. Affected Red Hat products consume Bouncy Castle transitively (e.g. resteasy, ceph, Keycloak/RHSSO, EAP) and are addressed via the delegated component trackers.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Red Hat is not aware of a mitigation for this flaw other than updating the affected Bouncy Castle component (bc-java 1.85, LTS 2.73.12, or BC-FJA 1.0.12/2.0.12/2.1.12) once available.