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TencentOS Server 4: nginx (TSSA-2026:0549)

critical Nessus Plugin ID 325860

Synopsis

The remote TencentOS Server 4 host is missing one or more security updates.

Description

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0549 advisory.

 Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:

 CVE-2026-42055:
 NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request.
 This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart.
 Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR.

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

Note that Nessus has not tested for this issue 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-20260549.xml

Plugin Details

Severity: Critical

ID: 325860

File Name: tencentos_TSSA_2026_0549.nasl

Version: 1.1

Type: Local

Published: 7/9/2026

Updated: 7/9/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.7

Percentile: 99.06

CVSS v2

Risk Factor: High

Base Score: 7.6

Temporal Score: 5.6

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

CVSS Score Source: CVE-2026-42055

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.1

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

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

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 7.2

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: p-cpe:/a:tencent:tencentos_server:nginx, cpe:/o:tencent:tencentos_server:4

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/6/2026

Vulnerability Publication Date: 6/17/2026

Reference Information

CVE: CVE-2026-42055

IAVA: 2026-A-0601