CVE-2026-45445

Technical Description

Issue summary: When an application drives an AES-OCB context through the

public EVP_Cipher() one-shot interface, the application-supplied

initialisation vector (IV) is silently discarded.

Impact summary: Every message encrypted under the same key uses the

same effective nonce regardless of the IV supplied by the caller,

resulting in (key, nonce) reuse and loss of confidentiality. If the

same code path is used to compute the authentication tag, the tag

depends only on the (key, IV) pair and not on the plaintext or

ciphertext, allowing universal forgery of arbitrary ciphertext from a

single captured message.

OpenSSL provides two ways to drive a cipher: the documented streaming

interface (EVP_CipherUpdate / EVP_CipherFinal_ex) and a lower-level

one-shot, EVP_Cipher(), whose documentation explicitly recommends

against use by applications in favour of EVP_CipherUpdate() and

EVP_CipherFinal_ex(). The OCB provider's streaming handler flushes

the application-supplied IV into the OCB contex

Remediation

Check the references section for vendor advisories and patches from openssl. Update openssl to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

Affected Products

References