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CVE-2026-32884

MEDIUMCVSS 5.9/10EPSS 0.16%

Last modified

CVE-2026-32884 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. 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. EPSS estimates a 0.16% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability
0.16%

5.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
Botan ProjectBotan< 3.11.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is 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.
How severe is CVE-2026-32884?
CVE-2026-32884 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.
How do I fix CVE-2026-32884?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-32884?

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Source: NVD / NIST