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AlmaLinux 9.6 [TuxCare] Security Update: gzip Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1783934943)

medium Nessus Plugin ID 362226

Synopsis

The AlmaLinux host is missing one or more security updates.

Description

The AlmaLinux 9.6 host has a package installed that is affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1783934943 advisory.

 - GNU gzip contains a vulnerability in the gzexe utility related to insecure temporary file handling. When the mktemp utility is not available in the user's PATH, gzexe falls back to constructing a temporary file path based solely on the process ID (PID). This predictable filename is created without exclusive access or existence checks. A local attacker can precreate the predicted temporary file path as a symbolic link pointing to an arbitrary file writable by the victim. When gzexe runs, it follows the symlink and overwrites the target file, resulting in a timeofcheck to timeofuse (TOCTOU) condition that allows arbitrary file overwrite. This issue has been fixed in the commit 4e6f8b24ab823146ab8776f0b7fe486ab34d4269 (CVE-2026-41991)

 - GNU gzip contains a global buffer overflow vulnerability in the LZH decompression logic caused by improper reuse of shared global state between different decompression formats within a single execution. GNU gzip maintains a global array that is shared across the LZ77, LZW, and LZH decompression routines and is not reinitialized between files processed in the same invocation. By decompressing a specially crafted LZW file followed by a specially crafted LZH file in a single gzip -d command, an attacker can poison the shared global state and subsequently trigger an outofbounds read in the LZH decoder. The LZH decompression logic follows stale values left in the shared array, causing reads past the end of the allocated global buffer. This issue has been fixed in commits 63dbf6b3b9e6e781df1a6a64e609b10e23969681 and e7378c2d421be6a286922374425680bbe9ad8b7d. (CVE-2026-41992)

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 gzip package based on the guidance in TuxCare advisory ALMALINUX9.6:CLSA-2026:1783934943.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1783934943

http://www.nessus.org/u?999655e4

Plugin Details

Severity: Medium

ID: 362226

File Name: tuxcare_alma_linux_9.6_CLSA-2026-1783934943.nasl

Version: 1.1

Type: Local

Published: 10/1/2026

Updated: 10/1/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.7

Percentile: 95.9

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-41992

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:H/I:N/A:N

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

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Threat Score: 4.6

Threat Vector: CVSS:4.0/E:U

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

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/AlmaLinux/release, Host/AlmaLinux/rpm-list, Host/OS/extended-third-party

Exploit Ease: No known exploits are available

Patch Publication Date: 7/13/2026

Vulnerability Publication Date: 6/29/2026

Reference Information

CVE: CVE-2026-41991, CVE-2026-41992

CLSA: 2026:1783934943