Detections
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TencentOS Server 3: grafana (TSSA-2026:1139)

high Nessus Plugin ID 365121

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-2026:1139 advisory.

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

 CVE-2026-33818:
 Enforce a recursion limit in Unmarshal to prevent stack exhaustion when parsing deeply-nested, recursive structures.

 CVE-2026-39820:
 Well-crafted inputs reaching ParseAddress, ParseAddressList, and ParseDate were able to trigger excessive CPU exhaustion and memory allocations.

 CVE-2026-42499:
 Pathological inputs could cause DoS through consumePhrase when parsing an email address according to RFC 5322.

 CVE-2026-42504:
 Decoding a maliciously-crafted MIME header containing many invalid encoded-words can consume excessive CPU.

 CVE-2026-56853:
 When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.

 CVE-2026-56858:
 Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.

 CVE-2026-56859:
 Previously, DecodeElement would reset the depth counter causing it to never fire; this could lead to stack exhaustion.

 CVE-2026-56860:
 Previously, resolving relative paths containing parent directory ('..') segments performed string conversions and buffer rewrites on each step, resulting in quadratic time complexity and high memory allocation overhead. Now, path resolution operates on a byte buffer using index-based backtracking for '..' segments, eliminating the quadratic time complexity and significantly reducing memory allocations.

 CVE-2026-56862:
 Handshake messages, such as KeyUpdate, are always considered as state-advancing, regardless of whether a handshake has been completed or not. As a result, a malicious client can keep sending KeyUpdate messages to force the server to keep performing key derivation operations indefinitely.

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-20261139.xml

Plugin Details

Severity: High

ID: 365121

File Name: tencentos_TSSA_2026_1139.nasl

Version: 1.1

Type: Local

Published: 10/12/2026

Updated: 10/12/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.17

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-39820

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

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

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

Vulnerability Information

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

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

Exploit Ease: No known exploits are available

Patch Publication Date: 9/2/2026

Vulnerability Publication Date: 5/7/2026

Reference Information

CVE: CVE-2026-33818, CVE-2026-39820, CVE-2026-42499, CVE-2026-42504, CVE-2026-56853, CVE-2026-56858, CVE-2026-56859, CVE-2026-56860, CVE-2026-56862