randombit botan up to 3.10.x X.509 Certificate certificate validation

Summaryinfo

A vulnerability classified as critical was found in randombit botan up to 3.10.x. The impacted element is an unknown function of the component X.509 Certificate Handler. Such manipulation leads to certificate validation. This vulnerability is traded as CVE-2026-32884. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in randombit botan up to 3.10.x. It has been rated as problematic. Affected by this issue is an unknown function of the component X.509 Certificate Handler. The manipulation with an unknown input leads to a certificate validation vulnerability. Using CWE to declare the problem leads to CWE-295. The product does not validate, or incorrectly validates, a certificate. Impacted is integrity. CVE summarizes:

Botan is a C++ cryptography library. Prior to version 3.11.0, during processing of an X.509 certificate path using name constraints which restrict the set of allowable DNS names, if no subject alternative name is defined in the end-entity certificate Botan would check that the CN was allowed by the DNS name constraints, even though this check is technically not required by RFC 5280. However this check failed to account for the possibility of a mixed-case CN. Thus a certificate with CN=Sub.EVIL.COM and no subject alternative name would bypasses an excludedSubtrees constraint for evil.com because the comparison is case-sensitive. This issue has been patched in version 3.11.0.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-32884 since 03/16/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1587.003.

Upgrading to version 3.11.0 eliminates this vulnerability.

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Productinfo

Vendor

• randombit

Name

• botan

Version

• 3.0
• 3.1
• 3.2
• 3.3
• 3.4
• 3.5
• 3.6
• 3.7
• 3.8
• 3.9
• 3.10

License

• open-source

Website

• Product: https://github.com/randombit/botan/

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