CVE-2026-45445
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk24th percentile - higher than 24% of all known CVEs
Summary
A vulnerability in OpenSSL causes the supplied IV to be silently discarded when using the EVP_Cipher() one-shot interface for AES-OCB. Every message encrypted with the same key uses the same effective nonce, leading to loss of confidentiality and enabling authentication tag forgery.
Risk Assessment
The organization risks that encrypted data can be decrypted by an attacker and message authentication can be forged, compromising both confidentiality and integrity.
Recommendation
Update OpenSSL to a patched version and avoid using the EVP_Cipher() interface for AES-OCB; instead, use the recommended streaming interface EVP_CipherUpdate/EVP_CipherFinal_ex.
Other vulnerabilities in OpenSSL
See all- CVE-2016-8610High
A denial of service flaw was found in OpenSSL 0.9.8, 1.0.1, 1.0.2 through 1.0.2h, and 1.1.0 in the way the TLS/SSL protocol defined processing of ALERT packets during a connection handshake. A remote attacker could use this flaw to make a TLS/SSL server consume an excessive amount of CPU and fail to accept connections from other clients.
- CVE-2017-3731High
CVE-2017-3731 affects SSL/TLS servers and clients running on 32-bit hosts that may crash due to an out-of-bounds read caused by a truncated packet. For OpenSSL 1.1.0, the crash can be triggered using the CHACHA20/POLY1305 cipher, and for OpenSSL 1.0.2 using RC4-MD5.
- CVE-2017-3730High
In OpenSSL 1.1.0 before 1.1.0d, a malicious server can supply bad parameters for a DHE or ECDHE key exchange, leading to the client attempting to dereference a NULL pointer, resulting in a client crash.
- CVE-2016-7054High
In OpenSSL 1.1.0 before 1.1.0c, TLS connections using *-CHACHA20-POLY1305 ciphersuites are susceptible to a DoS attack by corrupting larger payloads. This can result in an OpenSSL crash.
- CVE-2016-7052High
OpenSSL 1.0.2i has a vulnerability that allows remote attackers to cause application crashes by triggering a CRL operation, leading to a NULL pointer dereference.
- CVE-2016-6305High
The ssl3_read_bytes function in OpenSSL 1.1.0 before version 1.1.0a allows remote attackers to cause a denial of service (infinite loop) by triggering a zero-length record in an SSL_peek call.
- CVE-2016-6304High
Multiple memory leaks in t1_lib.c in OpenSSL before 1.0.1u, 1.0.2 before 1.0.2i, and 1.1.0 before 1.1.0a allow remote attackers to cause a denial of service (memory consumption) via large OCSP Status Request extensions.
- CVE-2016-6302High
The tls_decrypt_ticket function in OpenSSL before 1.1.0 does not consider the HMAC size during validation of the ticket length, allowing remote attackers to cause a denial of service via a ticket that is too short.
- CVE-2016-2179High
The DTLS implementation in OpenSSL before 1.1.0 does not properly restrict the lifetime of queue entries associated with unused out-of-order messages. This allows remote attackers to cause a denial of service (memory consumption) by maintaining many crafted DTLS sessions simultaneously.
- CVE-2016-2176High
The X509_NAME_oneline function in OpenSSL before 1.0.1t and 1.0.2 before 1.0.2h allows remote attackers to obtain sensitive information from process stack memory or cause a denial of service (buffer over-read) via crafted EBCDIC ASN.1 data.
Original NVD description (English source)
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.