--- id: CVE-2026-75803 title: |- Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the operation is finalized by calling the EVP_Cipher() function. Impact summary: … summary: |- Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the operation is finalized by calling the EVP_Cipher() function. Impact summary: … severity: critical cvss: 9.1 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N' cwe: - CWE-354 vendor: openssl product: openssl affected: - 'openssl >= 3.0.0, < 3.0.22' - 'openssl >= 3.4.0, < 3.4.7' - 'openssl >= 3.5.0, < 3.5.8' - 'openssl >= 3.6.0, < 3.6.4' - 'openssl >= 4.0.0, < 4.0.2' patched: - openssl 4.0.2 published: '2026-08-25' updated: '2026-09-11' sourceUpdated: '2026-09-11T21:17:17.823' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-75803' references: - url: >- https://github.com/openssl/openssl/commit/119ab9555dc62275bbd71f6f49529b1a44feba42 label: openssl-security@openssl.org - url: >- https://github.com/openssl/openssl/commit/3621257986e27e540bf96a11570929a6e5a9e05b label: openssl-security@openssl.org - url: >- https://github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a label: openssl-security@openssl.org - url: >- https://github.com/openssl/openssl/commit/bdeb0cd994d915342787f117ee75044f0dc36f34 label: openssl-security@openssl.org - url: >- https://github.com/openssl/openssl/commit/bf95f5f772e9362f87b25cfa2f8cb15d984865b9 label: openssl-security@openssl.org - url: 'https://openssl-library.org/news/secadv/20260825.txt' label: openssl-security@openssl.org - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-75803.json - url: 'https://access.redhat.com/security/cve/CVE-2026-75803' - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2523425' - url: 'https://www.cve.org/CVERecord?id=CVE-2026-75803' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-75803' - url: 'https://access.redhat.com/errata/RHSA-2026:42825' - url: 'https://access.redhat.com/errata/RHSA-2026:59641' - url: 'https://access.redhat.com/errata/RHSA-2026:59635' - url: 'https://access.redhat.com/errata/RHSA-2026:55543' - url: 'https://access.redhat.com/errata/RHSA-2026:62562' - url: 'https://access.redhat.com/errata/RHSA-2026:62563' - url: 'https://access.redhat.com/errata/RHSA-2026:59260' - url: 'https://access.redhat.com/errata/RHSA-2026:62786' tags: - nvd - csaf - vex - red-hat - score-dispute epss: 0.00221 epssPercentile: 0.11281 ingestedAt: '2026-09-12T00:03:49.031Z' scores: nvd: 9.1 vendor: 3.7 --- ## Overview Issue summary: ChaCha20-Poly1305 and AES-OCB decryption with an empty ciphertext can report success without verifying the supplied authentication tag when the operation is finalized by calling the EVP_Cipher() function. Impact summary: Applications calling EVP_Cipher() on an empty ciphertext and expecting the call to check the AEAD tag may accept forged messages. CWE: CWE-354 (Improper Validation of Integrity Check Value) Description: The EVP_Cipher() API call for AEAD ciphers behaves like a one shot encryption and decryption call. It also verifies the AEAD tag after the decryption operation. However for AES-OCB and ChaCha20-Poly1305 ciphers it skipped the AEAD tag verification when an empty ciphertext was passed to the function. The callers of this function might believe that a successful return indicates a valid AEAD tag for these ciphers, even when that has not truly been validated in this case. FIPS impact: no The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE as the affected algorithms are not FIPS approved and thus not implemented in the FIPS module. ## Affected - `openssl >= 3.0.0, < 3.0.22` - `openssl >= 3.4.0, < 3.4.7` - `openssl >= 3.5.0, < 3.5.8` - `openssl >= 3.6.0, < 3.6.4` - `openssl >= 4.0.0, < 4.0.2` ## Remediation Upgrade past the affected range: - `openssl 4.0.2` ## Vendor advisories - **Red Hat VEX** · Low · affected: Ansible Automation Orchestrator 2026, Confidential Cluster Operator, Confidential Compute Attestation, Lightspeed Core, Logging Subsystem for Red Hat OpenShift, Migration Toolkit for Applications 8, … · no fix planned: Ansible Automation Orchestrator 2026, Confidential Cluster Operator, Confidential Compute Attestation, Lightspeed Core, … · updated 2026-09-25 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-75803.json) - **RHSA-2026:42825** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-07-21 · [advisory](https://access.redhat.com/errata/RHSA-2026:42825) - **RHSA-2026:59641** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59641) - **RHSA-2026:59635** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59635) - **RHSA-2026:55543** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-17 · [advisory](https://access.redhat.com/errata/RHSA-2026:55543) - **RHSA-2026:62562** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62562) - **RHSA-2026:62563** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62563) - **RHSA-2026:59260** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-08-25 · [advisory](https://access.redhat.com/errata/RHSA-2026:59260) - **RHSA-2026:62786** · Red Hat · fixed in: Red Hat Hardened Images · released 2026-09-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:62786)