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CVE-2026-34580

CRITICAL CVSS 4.0: 9.3 EPSS 0.02%
Updated Apr 17, 2026
Botan_Project
Parameter Value
CVSS 9.3 (CRITICAL)
Fixed In 3.11.1
Type CWE-295 (Improper Certificate Validation)
Vendor Botan_Project
Public PoC No

Botan is a C++ cryptography library. In 3.11.0, the function Certificate_Store::certificate_known had a misleading name; it would return true if any certificate in the store had a DN (and subject key identifier, if set) matching that of the argument. It did not check that the cert it found and the cert it was passed were actually the same certificate.

In 3.11.0 an extension of path validation logic was made which assumed that certificate_known only returned true if the certificates were in fact identical. The impact is that if an end entity certificate is presented, and its DN (and subject key identifier, if set) match that of any trusted root, the end entity certificate is accepted immediately as if it itself were a trusted root. , This vulnerability is fixed in 3.11.1.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed

Impact Assessment

Confidentiality
High
Complete data leak
Integrity
High
Complete data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 1

Configuration From (including) Up to (excluding)
Botan_Project Botan
cpe:2.3:a:botan_project:botan:3.11.0:*:*:*:*:*:*:*

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