CVE-2026-45446

A flaw was found in OpenSSL. The implementations of AES-SIV (Advanced Encryption Standard - SIV) and AES-GCM-SIV (Advanced Encryption Standard - Galois/Counter Mode - SIV) incorrectly process authentication tags for empty messages. This vulnerability allows a remote attacker to forge empty messages with arbitrary Additional Authenticated Data (AAD) in applications that utilize these specific cipher modes within custom protocols and do not properly handle zero-length ciphertexts. This could lead to unauthorized data manipulation.

This flaw is rated as Low impact. It affects applications that utilize OpenSSL's AES-SIV or AES-GCM-SIV modes within custom protocols and specifically mishandle empty ciphertexts. Standard OpenSSL protocols, such as TLS, are not affected. Successful exploitation requires an application to use the EVP interface and to skip ciphertext updates when processing zero-length ciphertexts, representing an uncommon and non-default configuration.

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.

The vulnerability arises from specific application implementations using OpenSSL's AES-SIV or AES-GCM-SIV modes with custom protocols and an atypical handling of empty ciphertexts. As this scenario is not a default or commonly deployed configuration in Red Hat products, and no direct configuration or operational control exists to mitigate this specific flaw without patching, the following applies:

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.