Vulnerability in OpenSSL AES-SIV and AES-GCM-SIV Implementations

CVE-2026-45446

What is CVE-2026-45446?

The vulnerability arises from a flawed implementation of AES-SIV and AES-GCM-SIV ciphers in OpenSSL, where the authentication of Additional Authenticated Data (AAD) does not adequately verify when an empty ciphertext is provided. This allows an attacker to craft and send empty messages accompanied by arbitrary AAD, successfully bypassing authentication checks. Specifically, if the EVP_DecryptFinal_ex() function is called without prior invocation of the ciphertext update—with the ciphertext length being zero—the algorithm fails to recalculate the authentication tag, which retains a value of all zeros. As a result, any attacker can exploit this behavior under certain conditions, potentially compromising the application's security.

References