TencentOS Server 3: libxml2 (TSSA-2025:0642)

critical Nessus Plugin ID 276028

Synopsis

The remote TencentOS Server 3 host is missing one or more security updates.

Description

The version of Tencent Linux installed on the remote TencentOS Server 3 host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the TSSA-2025:0642 advisory.

Package updates are available for TencentOS Server 3 that fix the following vulnerabilities:

CVE-2025-6021:
A flaw was found in libxml2's xmlBuildQName function, where integer overflows in buffer size calculations can lead to a stack-based buffer overflow. This issue can result in memory corruption or a denial of service when processing crafted input.

CVE-2025-49794:
A use-after-free vulnerability was found in libxml2. This issue occurs when parsing XPath elements under certain circumstances when the XML schematron has the <sch:name path=.../> schema elements. This flaw allows a malicious actor to craft a malicious XML document used as input for libxml, resulting in the program's crash using libxml or other possible undefined behaviors.

CVE-2025-49796:
A vulnerability was found in libxml2. Processing certain sch:name elements from the input XML file can trigger a memory corruption issue. This flaw allows an attacker to craft a malicious XML input file that can lead libxml to crash, resulting in a denial of service or other possible undefined behavior due to sensitive data being corrupted in memory.

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.

Plugin Details

Severity: Critical

ID: 276028

File Name: tencentos_TSSA_2025_0642.nasl

Version: 1.1

Type: local

Family: Tencent Local Security Checks

Published: 11/20/2025

Updated: 11/20/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7.4

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

CVSS Score Source: CVE-2025-49796

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 8.2

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

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

Vulnerability Information

CPE: cpe:/o:tencent:tencentos_server:3, p-cpe:/a:tencent:tencentos_server:libxml2

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: 7/9/2025

Vulnerability Publication Date: 6/12/2025

Reference Information

CVE: CVE-2025-49794, CVE-2025-49796, CVE-2025-6021

IAVA: 2025-A-0707-S

Detections

Analytics