AEAD Forgeries with Empty Ciphertext When Using EVP_Cipher()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-75803
StatePUBLISHED
Assigneropenssl
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-25 13:19:29 UTC
Updated2026-08-28 19:46:29 UTC
DescriptionIssue 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.

Risk And Classification

EPSS: 0.001160000 probability, percentile 0.017920000 (date 2026-08-30)

Problem Types: CWE-354 | CWE-354 Improper Validation of Integrity Check Value

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA OpenSSL OpenSSL affected 4.0.0 4.0.2 semver Not specified
CNA OpenSSL OpenSSL affected 3.6.0 3.6.4 semver Not specified
CNA OpenSSL OpenSSL affected 3.5.0 3.5.8 semver Not specified
CNA OpenSSL OpenSSL affected 3.4.0 3.4.7 semver Not specified
CNA OpenSSL OpenSSL affected 3.0.0 3.0.22 semver Not specified

References

ReferenceSourceLinkTags
openssl-library.org/news/secadv/20260825.txt [email protected] openssl-library.org
github.com/openssl/openssl/commit/bdeb0cd994d915342787f117ee75044f0dc36f34 [email protected] github.com
github.com/openssl/openssl/commit/6c7aa6f8f6449b7fe0137ee8be65fcd239bd7d6a [email protected] github.com
github.com/openssl/openssl/commit/bf95f5f772e9362f87b25cfa2f8cb15d984865b9 [email protected] github.com
github.com/openssl/openssl/commit/119ab9555dc62275bbd71f6f49529b1a44feba42 [email protected] github.com
github.com/openssl/openssl/commit/3621257986e27e540bf96a11570929a6e5a9e05b [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Billy Brumley (Rochester Institute of Technology) (en)

CNA: Billy Brumley (Rochester Institute of Technology) (en)

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