Generation of Weak Initialization Vector (IV) Affecting openssl package, versions <1:3.5.5-4.el9_8
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL9-OPENSSL-17323863
- published12 Jun 2026
- disclosed9 Jun 2026
Introduced: 9 Jun 2026
NewCVE-2026-45445 (opens in a new tab)How to fix?
Upgrade RHEL:9 openssl to version 1:3.5.5-4.el9_8 or higher.
This issue was patched in RHSA-2026:25239.
NVD Description
Note: Versions mentioned in the description apply only to the upstream openssl package and not the openssl package as distributed by RHEL.
See How to fix? for RHEL:9 relevant fixed versions and status.
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 context before processing data; the one-shot handler did not. Every call to EVP_Cipher() on an AES-OCB context therefore ran with the all-zero key-derived offset state left by cipher initialisation, regardless of the caller's IV.
If EVP_EncryptFinal_ex() is subsequently used to obtain the authentication tag, the deferred IV setup runs at that point and clears the running checksum that should have been accumulated over the plaintext. The resulting tag is a function of (key, IV) only and verifies against any ciphertext produced under the same (key, IV) pair.
The OpenSSL SSL/TLS implementation is not affected: AES-OCB is not a TLS cipher suite, and libssl does not call EVP_Cipher() in any case. Applications that drive AES-OCB through the documented streaming AEAD API (EVP_CipherUpdate / EVP_CipherFinal_ex) are not affected. Only applications that combine the AES-OCB cipher with the EVP_Cipher() one-shot API are vulnerable.
The FIPS modules in 4.0, 3.6, 3.5, 3.4 and 3.0 are not affected by this issue, as AES-OCB is outside the OpenSSL FIPS module boundary.
References
- https://access.redhat.com/security/cve/CVE-2026-45445
- https://github.com/openssl/security/commit/323f0b6e7d530a4cb4336d50c88cb70f3ac2a451
- https://github.com/openssl/security/commit/787a6dfba81b7b09c1e05ab31396c0cd7c36b3f7
- https://github.com/openssl/security/commit/7ac4715234ee72d9f3c93426a2c08554b5b771af
- https://github.com/openssl/security/commit/843c9b94ca9c2ed248bb30127bb4f3d7af0d607c
- https://github.com/openssl/security/commit/983d54b5cce8d16147548ed1a37892d1720bbab6
- https://github.com/openssl/openssl/commit/323f0b6e7d530a4cb4336d50c88cb70f3ac2a451
- https://github.com/openssl/openssl/commit/787a6dfba81b7b09c1e05ab31396c0cd7c36b3f7
- https://github.com/openssl/openssl/commit/7ac4715234ee72d9f3c93426a2c08554b5b771af
- https://github.com/openssl/openssl/commit/843c9b94ca9c2ed248bb30127bb4f3d7af0d607c
- https://github.com/openssl/openssl/commit/983d54b5cce8d16147548ed1a37892d1720bbab6
- https://openssl-library.org/news/secadv/20260609.txt