CVE-2026-75803
Published:August 25, 2026
Updated:September 12, 2026
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 Packages
https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-3.4.0 <openssl-3.4.7Fix Suggestion:
Update to version openssl-3.4.7https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-3.0.0 <openssl-3.0.22Fix Suggestion:
Update to version openssl-3.0.22https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-3.6.0 <openssl-3.6.4Fix Suggestion:
Update to version openssl-3.6.4https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-4.0.0 <openssl-4.0.2Fix Suggestion:
Update to version openssl-4.0.2https://github.com/openssl/openssl.git (GITHUB):
Affected version(s) >=openssl-3.5.0 <openssl-3.5.8Fix Suggestion:
Update to version openssl-3.5.8Related Resources (10)
Do you need more information?
Contact UsCVSS v4
Base Score:
9.3
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
HIGH
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
9.1
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Validation of Integrity Check Value
EPSS
Base Score:
0.21