Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-3833

34
FAUCET Score

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.

First published: Apr 30, 2026Last modified: Jul 22, 2026

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:gnu:gnutls:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*
4.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
2.5
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.56%
Probability of exploitation in next 30 days
EPSS Percentile
43.5%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0056 is in the 16th percentile among its peer group of 8,915 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (7)

ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (jammy)Fixed in: 3.7.3-4ubuntu1.9
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (noble)Fixed in: 3.8.3-1.1ubuntu3.6
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (questing)Fixed in: 3.8.9-3ubuntu2.2
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (resolute)Fixed in: 3.8.12-2ubuntu1.1
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (bionic)Fixed in: 3.5.18-1ubuntu1.6+esm3
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (focal)Fixed in: 3.6.13-2ubuntu1.12+esm2
ubuntupatch availablevia ubuntu_usn
Product: gnutls28 (xenial)Fixed in: 3.4.10-4ubuntu1.9+esm3

Vendor Advisories (3)

ubuntuUSN-8502-1

GnuTLS vulnerabilities

Jul 6, 2026
ubuntuUSN-8284-1

GnuTLS vulnerabilities

May 20, 2026
microsoft2026-Apr/CVE-2026-3833Moderate

Gnutls: gnutls: policy bypass due to case-sensitive nameconstraints comparison

Apr 14, 2026

References

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
access.redhat.com / errata/RHSA-2026:30849
access.redhat.com / errata/RHSA-2026:30850
access.redhat.com / errata/RHSA-2026:32962
access.redhat.com / errata/RHSA-2026:33125
access.redhat.com / errata/RHSA-2026:41921
access.redhat.com / errata/RHSA-2026:43575
access.redhat.com / security/cve/CVE-2026-3833
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
gitlab.com / gnutls/gnutls/-/issues/1803
ExploitIssue TrackingVendor Advisory