Description
A flaw was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure.
Affected products
gnu: gnutls; redhat: hardened images; redhat: openshift container platform; redhat: enterprise linux
References10
- gitlab.com/gnutls/gnutls/-/issues/1803 ExploitIssue TrackingVendor Advisory
- gitlab.com/gnutls/gnutls/-/issues/1803 ExploitIssue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:13274 Issue TrackingThird Party Advisory
- access.redhat.com/errata/RHSA-2026:20611
- access.redhat.com/errata/RHSA-2026:20612
- access.redhat.com/errata/RHSA-2026:20613
- access.redhat.com/errata/RHSA-2026:26319
- access.redhat.com/errata/RHSA-2026:26409
- access.redhat.com/errata/RHSA-2026:29197
- access.redhat.com/errata/RHSA-2026:30004
Metrics
- CVSS 3.1
-
7.4
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS — exploit probability
- 1% percentile: 47 · as of 13 November 2026
- CWE
- CWE-178
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