Detections
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TencentOS Server 4: libssh2 (TSSA-2026:0572)

high Nessus Plugin ID 325859

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 multiple vulnerabilities as referenced in the TSSA-2026:0572 advisory.

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

 CVE-2026-58051:
 libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries before parsing populates them, so a parse failure reaching the cleanup path leaves libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker- influenceable attrs pointer in a connecting libssh2 client.

 CVE-2026-58050:
 libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

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-20260572.xml

Plugin Details

Severity: High

ID: 325859

File Name: tencentos_TSSA_2026_0572.nasl

Version: 1.1

Type: Local

Published: 7/9/2026

Updated: 7/9/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.2

Percentile: 96.77

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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

CVSS Score Source: CVE-2026-58050

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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:P/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 8.3

Threat Score: 6.9

Threat Vector: CVSS:4.0/E:P

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

CVSS Score Source: CVE-2026-58051

Vulnerability Information

CPE: p-cpe:/a:tencent:tencentos_server:libssh2, cpe:/o:tencent:tencentos_server:4

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/6/2026

Vulnerability Publication Date: 6/28/2026

Reference Information

CVE: CVE-2026-58050, CVE-2026-58051