Name of the Vulnerable Software and Affected Versions:
Botan versions prior to 3.5.0
Botan versions prior to 2.19.5
Description:
The issue is related to the processing of X.509 certificates in the Botan C++ cryptography library. Checking name constraints in these certificates is quadratic in the number of names and name constraints, which can lead to a denial of service. An attacker could exploit this by presenting a certificate chain with a large number of names in the `SubjectAlternativeName`, signed by a CA certificate with a large number of name constraints.
Recommendations:
For Botan versions prior to 3.5.0, update to version 3.5.0 to resolve the issue.
For Botan versions prior to 2.19.5, update to version 2.19.5 to partially address the issue.
As a temporary workaround, consider restricting the number of names in the `SubjectAlternativeName` field to minimize the risk of exploitation.