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AlmaLinux 9.6 [TuxCare] Security Update: dnsmasq / dnsmasq-utils Multiple Vulnerabilities (ALMALINUX9.6:CLSA-2026:1779437548)

high Nessus Plugin ID 360388

Synopsis

The AlmaLinux host is missing one or more security updates.

Description

The AlmaLinux 9.6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare ALMALINUX9.6:CLSA-2026:1779437548 advisory.

 - dnsmasqs extract_name() function can be abused to cause a heap buffer overflow, allowing an attacker to inject false DNS cache entries, which could result in DNS lookups to redirect to an attacker-controlled IP address, or to cause a DoS. (CVE-2026-2291)

 - A Denial of Service (DoS) vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet. (CVE-2026-4890)

 - A heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet. (CVE-2026-4891)

 - A heap-based out-of-bounds write vulnerability in the DHCPv6 implementation of dnsmasq allows local attackers to execute arbitrary code with root privileges via a crafted DHCPv6 packet. (CVE-2026-4892)

 - An information disclosure vulnerability in dnsmasq allows remote attackers to bypass source checks via a crafted DNS packet with RFC 7871 client subnet information. (CVE-2026-4893)

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 ALMALINUX9.6:CLSA-2026:1779437548.

See Also

https://cve.tuxcare.com/els/releases/CLSA-2026:1779437548

http://www.nessus.org/u?744e7406

Plugin Details

Severity: High

ID: 360388

File Name: tuxcare_alma_linux_9.6_CLSA-2026-1779437548.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

Percentile: 93.2

Vendor

Vendor Severity: Important

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-2291

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.9

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

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

CVSS Score Source: CVE-2026-4892

Vulnerability Information

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/22/2026

Vulnerability Publication Date: 5/11/2026

Reference Information

CVE: CVE-2026-2291, CVE-2026-4890, CVE-2026-4891, CVE-2026-4892, CVE-2026-4893

CLSA: 2026:1779437548