Detections
Analytics

TencentOS Server 2: gnutls (TSSA-2026:0943)

high Nessus Plugin ID 342054

Synopsis

The remote TencentOS Server 2 host is missing one or more security updates.

Description

The version of Tencent Linux installed on the remote TencentOS Server 2 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2026:0943 advisory.

 Package updates are available for TencentOS Server 2 that fix the following vulnerabilities:

 CVE-2026-3833:
 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.

 CVE-2026-42011:
 A flaw was found in gnutls. This vulnerability occurs because permitted name constraints were incorrectly ignored when previous Certificate Authorities (CAs) only had excluded name constraints. A remote attacker could exploit this to bypass critical name constraint checks during certificate validation. This bypass could lead to the acceptance of invalid certificates, potentially enabling spoofing or man-in-the-middle attacks against affected systems.

 CVE-2026-42012:
 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.

 CVE-2026-42013:
 A flaw was found in gnutls. When validating certificates, an oversized Subject Alternative Name (SAN) could cause the validation process to incorrectly fall back to checking the Common Name (CN) field. This could allow a remote attacker to bypass proper certificate validation, potentially leading to spoofing or man-in-the-middle attacks.

 CVE-2026-42014:
 A flaw was found in GnuTLS. The gnutls_pkcs11_token_set_pin function, used for changing the Security Officer PIN, can lead to a use-after-free vulnerability. This occurs when an attacker attempts to change the PIN with a NULL old PIN for a token that lacks a protected authentication path.

 CVE-2026-42015:
 A flaw was found in gnutls. An off-by-one error exists in the PKCS#12 bag element bounds check. This vulnerability allows an remote attacker to write past the internal array of a PKCS#12 bag when appending to a bag that already contains 32 elements. This memory corruption could lead to a denial of service (DoS) or potentially other unspecified impacts.

Tenable has extracted the preceding description block directly from the Tencent Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

See Also

https://mirrors.tencent.com/tlinux/errata/tssa-20260943.xml

Plugin Details

Severity: High

ID: 342054

File Name: tencentos_TSSA_2026_0943.nasl

Version: 1.1

Type: Local

Published: 9/1/2026

Updated: 9/1/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.59

CVSS v2

Risk Factor: High

Base Score: 7.1

Temporal Score: 5.6

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

CVSS Score Source: CVE-2026-3833

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 6.7

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:tencent:tencentos_server:2, p-cpe:/a:tencent:tencentos_server:gnutls

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/etc/os-release, Host/TencentOS/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/22/2026

Vulnerability Publication Date: 4/30/2026

Reference Information

CVE: CVE-2026-3833, CVE-2026-42011, CVE-2026-42012, CVE-2026-42013, CVE-2026-42014, CVE-2026-42015

IAVA: 2026-A-0405