GnuTLS Certificate dNSName/rfc822Name case sensitivity

CVSS Meta Temp Score
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CTI Interest Score
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7.1$0-$5k0.00

Summaryinfo

A vulnerability was found in GnuTLS and classified as critical. This impacts an unknown function of the component Certificate Handler. The manipulation of the argument dNSName/rfc822Name results in case sensitivity. This vulnerability is identified as CVE-2026-3833. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, was found in GnuTLS (the affected version is unknown). Affected is an unknown code of the component Certificate Handler. The manipulation of the argument dNSName/rfc822Name with an unknown input leads to a case sensitivity vulnerability. CWE is classifying the issue as CWE-178. The product does not properly account for differences in case sensitivity when accessing or determining the properties of a resource, leading to inconsistent results. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is shared for download at access.redhat.com. This vulnerability is traded as CVE-2026-3833 since 03/09/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/20/2026).

The vulnerability scanner Nessus provides a plugin with the ID 312106 (CentOS 9 : gnutls-3.8.10-4.el9), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (312106) and CERT Bund (WID-SEC-2026-1312). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • IBM MQ
  • Microsoft Azure Linux
  • Open Source GnuTLS

Productinfo

Type

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.1
VulDB Meta Temp Score: 7.1

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.4
NVD Vector: 🔒

CNA Base Score: 6.5
CNA Vector (redhat): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Case sensitivity
CWE: CWE-178 / CWE-697
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 312106
Nessus Name: CentOS 9 : gnutls-3.8.10-4.el9

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

03/09/2026 CVE reserved
04/30/2026 +51 days Advisory disclosed
04/30/2026 +0 days VulDB entry created
06/20/2026 +50 days VulDB entry last update

Sourcesinfo

Advisory: access.redhat.com
Status: Confirmed

CVE: CVE-2026-3833 (🔒)
GCVE (CVE): GCVE-0-2026-3833
GCVE (VulDB): GCVE-100-360336
CERT Bund: WID-SEC-2026-1312 - GnuTLS: Mehrere Schwachstellen

Entryinfo

Created: 04/30/2026 20:11
Updated: 06/20/2026 01:33
Changes: 04/30/2026 20:11 (61), 05/01/2026 22:51 (7), 05/05/2026 10:19 (2), 05/27/2026 07:36 (11), 06/04/2026 02:53 (1), 06/20/2026 01:33 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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