CVE-2026-103601

Name of the Vulnerable Software and Affected Versions bc-csharp versions prior to 2.7.0

Description The CCM (CcmBlockCipher) and DSTU 7624 CCM (KCcmBlockCipher) AEAD modes release unverified plaintext. A remote attacker can obtain decryptions of chosen ciphertexts by sending forged messages to an application that allows the output buffer of a failed decryption to be observed, such as through logging or buffer reuse. This occurs because the decryption process writes the recovered plaintext into the caller-supplied output buffer before verifying the authentication tag and fails to clear it if the check fails. This issue only affects decryption into a caller-supplied buffer; methods returning a newly allocated array are not impacted.

Recommendations Update bc-csharp to version 2.7.0 or later.