Amazon Linux 2023 : dnsmasq, dnsmasq-utils (ALAS2023-2026-1729)

high Nessus Plugin ID 316834

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Synopsis

The remote Amazon Linux 2023 host is missing a security update.

Description

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1729 advisory.

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)

A buffer overflow in dnsmasq's extract_addresses() function allows an attacker to trigger a heap out-of- bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record's end. (CVE-2026-5172)

Tenable has extracted the preceding description block directly from the tested product 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

Run 'dnf update dnsmasq --releasever 2023.11.20260526' or or 'dnf update --advisory ALAS2023-2026-1729 --releasever 2023.11.20260526' to update your system.

Plugin Details

Severity: High

ID: 316834

File Name: al2023_ALAS2023-2026-1729.nasl

Version: 1.3

Type: Local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 5/26/2026

Updated: 6/2/2026

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 8.3

Temporal Score: 6.5

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

CVSS Score Source: CVE-2026-4892

CVSS v3

Risk Factor: High

Base Score: 8.4

Temporal Score: 7.6

Vector: CVSS:3.0/AV:L/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

Vulnerability Information

CPE: p-cpe:/a:amazon:linux:dnsmasq, p-cpe:/a:amazon:linux:dnsmasq-debuginfo, p-cpe:/a:amazon:linux:dnsmasq-utils, p-cpe:/a:amazon:linux:dnsmasq-debugsource, p-cpe:/a:amazon:linux:dnsmasq-utils-debuginfo, cpe:/o:amazon:linux:2023

Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/25/2026

Vulnerability Publication Date: 5/11/2026

Reference Information

CVE: CVE-2026-4890, CVE-2026-4891, CVE-2026-4892, CVE-2026-4893, CVE-2026-5172

IAVA: 2026-A-0450

Detections

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