CVE-2026-3833

high

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.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2445763

https://access.redhat.com/security/cve/CVE-2026-3833

https://access.redhat.com/errata/RHSA-2026:82888

https://access.redhat.com/errata/RHSA-2026:82857

https://access.redhat.com/errata/RHSA-2026:82372

https://access.redhat.com/errata/RHSA-2026:82354

https://access.redhat.com/errata/RHSA-2026:82347

https://access.redhat.com/errata/RHSA-2026:82322

https://access.redhat.com/errata/RHSA-2026:82304

https://access.redhat.com/errata/RHSA-2026:74674

https://access.redhat.com/errata/RHSA-2026:72502

https://access.redhat.com/errata/RHSA-2026:67857

https://access.redhat.com/errata/RHSA-2026:65851

https://access.redhat.com/errata/RHSA-2026:65839

https://access.redhat.com/errata/RHSA-2026:62549

https://access.redhat.com/errata/RHSA-2026:62409

https://access.redhat.com/errata/RHSA-2026:60019

https://access.redhat.com/errata/RHSA-2026:59831

https://access.redhat.com/errata/RHSA-2026:58981

https://access.redhat.com/errata/RHSA-2026:57402

https://access.redhat.com/errata/RHSA-2026:43575

https://access.redhat.com/errata/RHSA-2026:41921

https://access.redhat.com/errata/RHSA-2026:33125

https://access.redhat.com/errata/RHSA-2026:32962

https://access.redhat.com/errata/RHSA-2026:30850

https://access.redhat.com/errata/RHSA-2026:30849

https://access.redhat.com/errata/RHSA-2026:30004

https://access.redhat.com/errata/RHSA-2026:29197

https://access.redhat.com/errata/RHSA-2026:26409

https://access.redhat.com/errata/RHSA-2026:26319

https://access.redhat.com/errata/RHSA-2026:20613

https://access.redhat.com/errata/RHSA-2026:20612

https://access.redhat.com/errata/RHSA-2026:20611

https://access.redhat.com/errata/RHSA-2026:13274

Details

Source: Mitre, NVD

Published: 2026-04-30

Updated: 2026-10-14

Risk Information

CVSS v2

Base Score: 7.1

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:N

Severity: High

CVSS v3

Base Score: 7.4

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

Severity: High

EPSS

EPSS: 0.00565