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CVE-2026-45445— AES-OCB IV Ignored on EVP_Cipher() Path

Quick assessment

Affected
OpenSSL OpenSSL
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

OpenSSL是OpenSSL团队的一个开源的能够实现安全套接层（SSLv2/v3）和安全传输层（TLSv1）协议的通用加密库。该产品支持多种加密算法，包括对称密码、哈希算法、安全散列算法等。 OpenSSL存在安全漏洞，该漏洞源于AES-OCB上下文中EVP_Cipher()单次接口丢弃应用提供的初始化向量，导致相同密钥下所有消息使用相同有效nonce，造成密钥重用和机密性丧失，且认证标签仅依赖于密钥和IV对，允许从单个捕获消息伪造任意密文。

AI Predicted 8.1 Difficulty: Easy EPSS 0.70% · P52

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 5

VendorProduct Version RangeStatus
OpenSSL OpenSSL 4.0.0< 4.0.1 affected
3.6.0< 3.6.3 affected
3.5.0< 3.5.7 affected
3.4.0< 3.4.6 affected
3.0.0< 3.0.21 affected
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I. Basic Information for CVE-2026-45445

Vulnerability Information
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Vulnerability Title
AES-OCB IV Ignored on EVP_Cipher() Path
Source: CVE Program / CVE List V5
Vulnerability 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 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.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
缺少必要的密码学步骤
Source: CVE Program / CVE List V5
Vulnerability Title
OpenSSL 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
OpenSSL是OpenSSL团队的一个开源的能够实现安全套接层（SSLv2/v3）和安全传输层（TLSv1）协议的通用加密库。该产品支持多种加密算法，包括对称密码、哈希算法、安全散列算法等。 OpenSSL存在安全漏洞，该漏洞源于AES-OCB上下文中EVP_Cipher()单次接口丢弃应用提供的初始化向量，导致相同密钥下所有消息使用相同有效nonce，造成密钥重用和机密性丧失，且认证标签仅依赖于密钥和IV对，允许从单个捕获消息伪造任意密文。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
OpenSSL OpenSSL 4.0.0 ~ 4.0.1 -

II. Public POCs for CVE-2026-45445

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III. Intelligence Information for CVE-2026-45445

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Patches & Fixes for CVE-2026-45445 (5)

Vendor Advisories for CVE-2026-45445 (1)

Same Patch Batch · OpenSSL · 2026-06-09 · 18 CVEs total

CVE-2026-45447 Heap Use-After-Free in the PKCS7_verify() Function
CVE-2026-34183 Unbounded Memory Growth in the QUIC PATH_CHALLENGE Handler
CVE-2026-34181 PKCS#12 Files with PBMAC1 Are Accepted with Short HMAC Keys
CVE-2026-34180 Heap Buffer Over-read in ASN.1 Content Parsing
CVE-2026-34182 CMS AuthEnvelopedData Processing May Accept Forged Messages
CVE-2026-9076 Out-of-Bounds Read in CMS Password-Based Decryption
CVE-2026-35188 Double-free When Checking OCSP Stapled Response
CVE-2026-7383 Possible Heap Buffer Overflow in ASN.1 Multibyte String Conversion
CVE-2026-45446 Incorrect Tag Processing for Empty Messages in AES-GCM-SIV and AES-SIV modes
CVE-2026-42771 Possible Out of Bounds Read in X509_VERIFY_PARAM_set1_email()
CVE-2026-42768 Multi-RecipientInfo Bleichenbacher Oracle in CMS_decrypt() and PKCS7_decrypt()
CVE-2026-42769 Trust-Anchor Substitution via cert/issuer Typo in CMP rootCaKeyUpdate
CVE-2026-42767 NULL Pointer Dereference in CRMF EncryptedValue Decryption
CVE-2026-42766 Possible NULL Dereference in Password-Based CMS Decryption
CVE-2026-42764 NULL Pointer Dereference in QUIC Server Initial Packet Handling
CVE-2026-42770 FFC-DH Peer Validation Uses Attacker-Supplied q
CVE-2026-42765 NULL Dereference in Certificate Verification with OCSP Checking

IV. Related Vulnerabilities

Same product: OpenSSL
Same vendor: OpenSSL
Same weakness: CWE-325

V. Comments for CVE-2026-45445

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