SEPTEMBER 17, 2026
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Case File

CVE-2026-75803

CRITICAL · CVSS 9.1 EPSS 0.22% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-25 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Applications utilizing the EVP_Cipher() function for AES-OCB and ChaCha20-Poly1305 ciphers are vulnerable when processing empty ciphertext, as the function may incorrectly report success without validating the authentication tag. This flaw can lead to the acceptance of forged messages, undermining data integrity and security. Developers and security teams working with these cryptographic implementations should prioritize addressing this vulnerability to prevent potential exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

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CVE
CVE-2026-75803
Severity
CRITICAL
CVSS
9.1
EPSS
0.22%

Original NVD Description

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.

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