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AlmaLinux 9.2 [TuxCare] Security Update: compat-libpthread-nonshared / glibc / glibc-all-langpacks / etc Multiple Vulnerabilities (ALMALINUX9.2:CLSA-2026:1791894819)

critical Nessus Plugin ID 368030

Synopsis

The AlmaLinux host is missing one or more security updates.

Description

The AlmaLinux 9.2 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.2:CLSA-2026:1791894819 advisory.

 - Passing an effectively empty string to the `,ccs=` syntax extension of the mode argument in the `fopen` function in the GNU C Library version 2.45 or earlier may result in a heap buffer overflow when the mode string input to the function is attacker controlled. This usage pattern is not seen in applications in common GNU/Linux distributions and applications that process user-supplied values for `ccs` should not pass them through without validation. (CVE-2026-18374)

 - Calling tdelete on a sufficiently deep tree in the GNU C Library version 2.1 to 2.44 may write one pointer past the end of an alloca-allocated array on the stack, which may crash the application. The tdelete implementation keeps an explicit stack of parent nodes for rebalancing, which is grown as needed while descending the tree. Two rebalancing branches push an additional entry without checking the capacity, and write past the array when the stack is exactly full. Triggering this requires a node at a depth of exactly 40 (or 40 plus a multiple of 20), which implies a tree with at least a million nodes, so an attacker must drive a large number of insertions and deletions through an application that uses tsearch and tdelete. The written value is a pointer into a tree node and is not directly attacker controlled. No affected application in common distributions has been identified. (CVE-2026-19542)

 - Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C Library version 2.34 to version 2.43 could, with a crafted response from the configured DNS server, result in a violation of the DNS specification that causes the application to treat a non-answer section of the DNS response as a valid answer. (CVE-2026-4437)

 - Calling gethostbyaddr or gethostbyaddr_r with a configured nsswitch.conf that specifies the library's DNS backend in the GNU C library version 2.34 to version 2.43 could result in an invalid DNS hostname being returned to the caller in violation of the DNS specification. (CVE-2026-4438)

 - Calling wordexp with WRDE_APPEND in the GNU C Library version 2.0 to version 2.43 can cause the interface to return invalid memory in the we_wordv member, which on subsequent calls to wordfree may abort the process. (CVE-2026-6368)

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 based on the guidance in TuxCare advisory ALMALINUX9.2:CLSA-2026:1791894819.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1791894819

http://www.nessus.org/u?4d267d68

Plugin Details

Severity: Critical

ID: 368030

File Name: tuxcare_alma_linux_9.2_CLSA-2026-1791894819.nasl

Version: 1.1

Type: Local

Published: 10/20/2026

Updated: 10/20/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.73

Vendor

Vendor Severity: Moderate

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5

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

CVSS Score Source: CVE-2026-4437

CVSS v3

Risk Factor: Medium

Base Score: 5.6

Temporal Score: 5.1

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

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

CVSS Score Source: CVE-2026-19542

CVSS v4

Risk Factor: Critical

Base Score: 9

Threat Score: 7.8

Threat Vector: CVSS:4.0/E:P

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

CVSS Score Source: CVE-2026-6791

Vulnerability Information

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/13/2026

Vulnerability Publication Date: 2/5/2026

Reference Information

CVE: CVE-2026-18374, CVE-2026-19542, CVE-2026-4437, CVE-2026-4438, CVE-2026-6368, CVE-2026-6791, CVE-2026-77117, CVE-2026-80489

CLSA: 2026:1791894819