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AlmaLinux 8 : dnsmasq (ALSA-2026:20589)

high Nessus Plugin ID 316889

Synopsis

The remote AlmaLinux host is missing one or more security updates.

Description

The remote AlmaLinux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALSA-2026:20589 advisory.

 * dnsmasq: dnsmasq: heap buffer overflow in cache via NAME_ESCAPE expansion (CVE-2026-2291)
 * dnsmasq: NSEC bitmap parsing infinite loop (CVE-2026-4890)
 * dnsmasq: RRSIG rdlen underflow leading to heap OOB read (CVE-2026-4891)
 * dnsmasq: DHCPv6 CLID buffer overflow in helper process (CVE-2026-4892)
 * dnsmasq: Broken ECS source validation bypass (CVE-2026-4893)

Tenable has extracted the preceding description block directly from the AlmaLinux 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 dnsmasq and / or dnsmasq-utils packages.

See Also

https://errata.almalinux.org/8/ALSA-2026-20589.html

https://access.redhat.com/errata/RHSA-2026:20589

Plugin Details

Severity: High

ID: 316889

File Name: alma_linux_ALSA-2026-20589.nasl

Version: 1.1

Type: Local

Published: 5/27/2026

Updated: 5/27/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 8.3

Temporal Score: 6.1

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: 7.3

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:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:alma:linux:8::sap_hana, cpe:/o:alma:linux:8::nfv, cpe:/o:alma:linux:8::highavailability, cpe:/o:alma:linux:8::powertools, cpe:/o:alma:linux:8::realtime, cpe:/o:alma:linux:8::resilientstorage, cpe:/o:alma:linux:8, cpe:/o:alma:linux:8::baseos, p-cpe:/a:alma:linux:dnsmasq, p-cpe:/a:alma:linux:dnsmasq-utils, cpe:/o:alma:linux:8::sap, cpe:/o:alma:linux:8::appstream, cpe:/o:alma:linux:8::supplementary

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

Exploit Ease: No known exploits are available

Patch Publication Date: 5/26/2026

Vulnerability Publication Date: 5/11/2026

Reference Information

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

CWE: 122, 125, 131, 20, 835

RHSA: 2026:20589