CVE-2026-32884 Botan: Case-Insensitive CN Values Bypass DNS excludedSubtrees Name Constraints (RFC 5280 Violation)

What is CVE-2026-32884?

CVE-2026-32884 is a medium-severity vulnerability in randombit botan, published on 30 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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.

Weakness: CWE-295

Which versions are affected by CVE-2026-32884?

It affects 1 product.

Products include Botan Project Botan.

How do I fix CVE-2026-32884?

Upgrade to a fixed version.

Is CVE-2026-32884 being exploited?

There is no known exploitation of CVE-2026-32884 in the wild and no public exploit code.

Other vulnerabilities in randombit botan

• CVE-2021-24115 Information disclosure in n/a Critical 9.8
• CVE-2018-9127 Security feature bypass in n/a Critical 9.8
• CVE-2015-7826 Security feature bypass in n/a Critical 9.8
• CVE-2016-6878 Other in n/a Critical 9.8
• CVE-2016-9132 Integer overflow in n/a Critical 9.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2026-32884, AZL-81180, DEBIAN-CVE-2026-32884, GHSA-7c3g-7763-ggj5, UBUNTU-CVE-2026-32884, openSUSE-SU-2026:20566-1.