GnuTLS certificate validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.3$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in GnuTLS. This affects an unknown function. Performing a manipulation results in certificate validation. This vulnerability is known as CVE-2026-42012. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in GnuTLS (affected version unknown). This affects an unknown functionality. The manipulation with an unknown input leads to a certificate validation vulnerability. CWE is classifying the issue as CWE-295. The product does not validate, or incorrectly validates, a certificate. This is going to have an impact on integrity. The summary by CVE is:

A flaw was found in gnutls. A remote attacker could exploit this vulnerability by presenting a specially crafted certificate that contains Uniform Resource Identifier (URI) or Service (SRV) Subject Alternative Names (SANs). This could cause the certificate validation process to incorrectly fall back to checking DNS hostnames against the Common Name (CN), potentially allowing the attacker to spoof legitimate services or intercept sensitive information.

It is possible to read the advisory at access.redhat.com. This vulnerability is uniquely identified as CVE-2026-42012 since 04/23/2026. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 06/20/2026). The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 316551 (Debian dla-4595 : gnutls-bin - security update), 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 (316551) and CERT Bund (WID-SEC-2026-1312). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.1
CNA Vector (redhat): 🔒

CVSSv2info

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

Exploitinginfo

Class: Certificate validation
CWE: CWE-295 / CWE-287
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: 316551
Nessus Name: Debian dla-4595 : gnutls-bin - security update

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

04/23/2026 CVE reserved
05/27/2026 +34 days Advisory disclosed
05/27/2026 +0 days VulDB entry created
06/20/2026 +23 days VulDB entry last update

Sourcesinfo

Advisory: RHSA-2026:20611
Status: Not defined

CVE: CVE-2026-42012 (🔒)
GCVE (CVE): GCVE-0-2026-42012
GCVE (VulDB): GCVE-100-365835
CERT Bund: WID-SEC-2026-1312 - GnuTLS: Mehrere Schwachstellen

Entryinfo

Created: 05/27/2026 06:25
Updated: 06/20/2026 01:56
Changes: 05/27/2026 06:25 (61), 05/29/2026 23:32 (2), 06/04/2026 03:07 (7), 06/20/2026 01:56 (1)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Discussion

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