EUVD-2026-65488
GHSA-vr27-9w4v-hjw2
Severity by source
Network vector because forged messages are submitted remotely; AC:H because empty ciphertext is a specific edge-case condition; no confidentiality or availability impact from tag forgery alone.
Lifecycle Timeline
3DescriptionCVE.org
AEAD Forgeries with Empty Ciphertext When Using EVP_Cipher()
AnalysisAI
AEAD authentication tag forgery in OpenSSL's EVP_Cipher() API enables an attacker to produce a cryptographically valid authentication tag for an empty ciphertext without knowledge of the secret key, bypassing the integrity and authenticity guarantees of AEAD cipher modes such as AES-GCM or ChaCha20-Poly1305. Any application invoking EVP_Cipher() with an AEAD mode and processing empty or zero-length ciphertexts is affected. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target application calls EVP_Cipher() specifically - not EVP_EncryptFinal_ex(), EVP_AEAD_CTX_seal(), or other AEAD APIs - with an AEAD cipher mode (e.g., AES-GCM, AES-CCM, ChaCha20-Poly1305) enabled. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | No CVSS vector, EPSS score, or KEV status was provided, making quantitative risk assessment depend entirely on first-principles analysis of the vulnerability class. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker targeting a service that uses OpenSSL EVP_Cipher() in an AEAD mode - such as a custom TLS extension handler, an encrypted message queue, or a file integrity system - sends a crafted message with an empty ciphertext body and a forged authentication tag. Because the tag verification step in EVP_Cipher() does not correctly handle zero-length ciphertext, the tag passes validation, and the service accepts the forged message as authentic. … |
| Remediation | The primary remediation is to apply the patch released by OpenSSL and re-package the updated libssl/libcrypto through distribution channels; however, no exact fixed version number was supplied in the input data and cannot be independently confirmed from the available intelligence. … Detailed patch versions, workarounds, and compensating controls in full report. |
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