CVE-2026-3833
Medium
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.
SeverityMedium
CVSS6.5
Exploit probability—
Product
Gnutls
PublishedApr 30, 2026
First seenApr 30, 2026
Weakness typeCWE-178CWE-178
How to fix
Vendor advisories
- gitlab.com/gnutls/gnutls/-/issues/1803
- access.redhat.com/errata/RHSA-2026:13274
- 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
- access.redhat.com/errata/RHSA-2026:30849
- access.redhat.com/errata/RHSA-2026:30850
- access.redhat.com/errata/RHSA-2026:32962
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| gnu gnutls | No range specified | — |
| redhat hardened_images | No range specified | — |
| redhat openshift_container_platform | 4.0 | — |
| redhat enterprise_linux | 6.0, 7.0, 8.0, 9.0, 10.0 | — |
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