TencentOS Server 3: tar (TSSA-2026:1146)

medium Nessus Plugin ID 365139

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-2026:1146 advisory.

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

CVE-2025-45582:
GNU Tar through 1.35 allows file overwrite via directory traversal in crafted TAR archives, with a certain two-step process. First, the victim must extract an archive that contains a ../ symlink to a critical directory. Second, the victim must extract an archive that contains a critical file, specified via a relative pathname that begins with the symlink name and ends with that critical file's name. Here, the extraction follows the symlink and overwrites the critical file. This bypasses the protection mechanism of Member name contains '..' that would occur for a single TAR archive that attempted to specify the critical file via a ../ approach. For example, the first archive can contain x -> ../../../../../home/victim/.ssh and the second archive can contain x/authorized_keys. This can affect server applications that automatically extract any number of user-supplied TAR archives, and were relying on the blocking of traversal. This can also affect software installation processes in which tar xf is run more than once (e.g., when installing a package can automatically install two dependencies that are set up as untrusted tarballs instead of official packages).

CVE-2026-5704:
A flaw was found in tar. A remote attacker could exploit this vulnerability by crafting a malicious archive, leading to hidden file injection with fully attacker-controlled content. This bypasses pre- extraction inspection mechanisms, potentially allowing an attacker to introduce malicious files onto a system without detection.

CVE-2026-18477:
A TOCTOU (Time-of-Check Time-of-Use) vulnerability in GNU tar's incremental dumpdir 'X' rename handling allows a local attacker with write access to a directory being backed up to influence the restore process if the attacker has access to the system where the restore is being performed. During restoration, files or directories may be created, renamed or overwritten outside the intended extraction directory. This could lead to unauthorized file modification or, in some cases, privilege escalation. Exploitation does not require the attacker to modify or craft the archive, and standard backup and restore workflowsincluding extracting into a newly created directory without using the -P option do not mitigate the issue.

CVE-2026-18508:
A flaw was found in GNU tar. When extracting an archive with the --one-top-level option, hardlink targets are not confined to the designated top-level directory and may resolve relative to the extraction working directory. A crafted archive can create hardlinks that escape the intended boundary and, when combined with a preexisting symbolic link under the working directory, may allow writing outside that boundary during a single extraction.

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: Medium

ID: 365139

File Name: tencentos_TSSA_2026_1146.nasl

Version: 1.1

Type: Local

Family: Tencent Local Security Checks

Published: 10/12/2026

Updated: 10/12/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.62

CVSS v2

Risk Factor: Medium

Base Score: 4.9

Temporal Score: 3.8

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

CVSS Score Source: CVE-2026-5704

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5

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

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:tar

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: 9/22/2026

Vulnerability Publication Date: 7/11/2025

Reference Information

CVE: CVE-2025-45582, CVE-2026-18477, CVE-2026-18508, CVE-2026-5704

Detections

Analytics