CVE-2026-45445 is a high-severity (CVSS 7.5) CWE-325 vulnerability. A fix is available — see the affected versions and patch details below.
AES-OCB IV Ignored on EVP_Cipher() Path
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-45445.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2026-45445 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 380,526 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
Affected Products
opensslopensslDetection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Fix
Upgrade the affected component to the fixed release for CVE-2026-45445, or apply your distribution's backported patch — distro builds are often patched at an older version number, so check your vendor's advisory rather than the upstream version alone.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Fixing This On Your OS
If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.
This is a Moderate severity flaw where applications utilizing the AES-OCB cipher through OpenSSL's EVP_Cipher() one-shot interface may silently discard the provided initialization vector (IV). This leads to nonce reuse, compromising confidentiality and enabling universal forgery of authentication tags. Red Hat…
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.Source: Red Hat security advisory for CVE-2026-45445 (CC BY 4.0)
| Product | Fixed in | Advisory |
|---|---|---|
| Red Hat Enterprise Linux 10 | openssl-1:3.5.5-4.el10_2 | RHSA-2026:25237 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | openssl-1:3.2.2-16.el10_0.7 | RHSA-2026:71542 |
| Red Hat Enterprise Linux 9 | openssl-1:3.5.5-4.el9_8 | RHSA-2026:25239 |
| Cert Manager support for Red Hat OpenShift release 1.20 | cert-manager/cert-manager-trust-manager-rhel9:1790598593 | RHSA-2026:72502 |
| Cost Management 4 | costmanagement/costmanagement-metrics-rhel9-operator:1783539156 | RHSA-2026:39981 |
| Red Hat Discovery 2 | discovery/discovery-server-rhel9:1782159791 | RHSA-2026:29197 |
| Red Hat Hardened Images | chunkah-main-0.6.0-3.hum1 | RHSA-2026:42825 |
| Red Hat Hardened Images | python-cryptography-main-50.0.0-1.hum1 | RHSA-2026:55543 |
Frequently Asked Questions
Is CVE-2026-45445 in your dependencies?
Find it across , including transitive dependencies.