Vulnerability in Botan Project
CVE-2026-32884
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.
Vulnerability class: Improper Certificate Validation
EPSS: 0.002 (5.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.
Affected products
- Botan_project Botan
- Randombit Botan — versions < 3.11.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-32884?
- CVE-2026-32884 is a medium-severity vulnerability in Botan Project, classified under Improper Certificate Validation. CVSS score: 5.9/10. Published 2026-03-30.
- How severe is CVE-2026-32884?
- Medium severity. CVSS v3 base score is 5.9 out of 10.