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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.

PUBLISHED Reserved 2026-03-09 | Published 2026-04-30 | Updated 2026-05-04 | Assigner redhat




MEDIUM: 6.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Problem types

Improper Handling of Case Sensitivity

Product status

Default status
unaffected

Any version before 3.8.13
affected

Default status
affected

3.8.13-1.hum1 (rpm) before *
unaffected

Default status
affected

Default status
affected

Default status
affected

Default status
affected

Default status
affected

Default status
affected

Timeline

2026-03-09:Reported to Red Hat.
2026-04-30:Made public.

References

gitlab.com/gnutls/gnutls/-/issues/1803 exploit

access.redhat.com/errata/RHSA-2026:13274 (RHSA-2026:13274) vendor-advisory

access.redhat.com/security/cve/CVE-2026-3833 vdb-entry

bugzilla.redhat.com/show_bug.cgi?id=2445763 (RHBZ#2445763) issue-tracking

gitlab.com/gnutls/gnutls/-/issues/1803

cve.org (CVE-2026-3833)

nvd.nist.gov (CVE-2026-3833)

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