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.
Advisories

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Fixes

Solution

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Workaround

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History

Wed, 08 Apr 2026 19:45:00 +0000

Type Values Removed Values Added
First Time appeared Randombit
Randombit botan
Vendors & Products Randombit
Randombit botan

Wed, 08 Apr 2026 19:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 08 Apr 2026 12:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 9.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N'}

threat_severity

Important


Tue, 07 Apr 2026 21:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Botan has a certificate authentication bypass due to trust anchor confusion
Weaknesses CWE-295
References
Metrics cvssV4_0

{'score': 9.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-04-08T15:24:01.286Z

Reserved: 2026-03-30T16:56:30.999Z

Link: CVE-2026-34580

cve-icon Vulnrichment

Updated: 2026-04-08T15:23:58.256Z

cve-icon NVD

Status : Received

Published: 2026-04-07T22:16:22.647

Modified: 2026-04-07T22:16:22.647

Link: CVE-2026-34580

cve-icon Redhat

Severity : Important

Publid Date: 2026-04-07T21:12:09Z

Links: CVE-2026-34580 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-08T19:34:10Z

Weaknesses