Debian dla-4625 : dnsmasq - security update

high Nessus Plugin ID 320466

Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4625 advisory.

- ------------------------------------------------------------------------- Debian LTS Advisory DLA-4625-1 [email protected] https://www.debian.org/lts/security/ Arnaud Rebillout June 10, 2026 https://wiki.debian.org/LTS
- -------------------------------------------------------------------------

Package : dnsmasq Version : 2.85-1+deb11u2 CVE ID : CVE-2026-2291 CVE-2026-4890 CVE-2026-4891 CVE-2026-4892 CVE-2026-4893

Several vulnerabilities have been discovered in dnsmasq, a caching DNS proxy and DHCP/TFTP server.

CVE-2026-2291

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-2026-4890

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-2026-4891

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-2026-4892

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-2026-4893

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

For Debian 11 bullseye, these problems have been fixed in version 2.85-1+deb11u2.

We recommend that you upgrade your dnsmasq packages.

For the detailed security status of dnsmasq please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/dnsmasq

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian 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

Upgrade the dnsmasq packages.

Plugin Details

Severity: High

ID: 320466

File Name: debian_DLA-4625.nasl

Version: 1.1

Type: Local

Agent: unix

Family: Debian Local Security Checks

Published: 6/11/2026

Updated: 6/11/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

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: 8.4

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

CVSS Score Source: CVE-2026-4892

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, p-cpe:/a:debian:debian_linux:dnsmasq, p-cpe:/a:debian:debian_linux:dnsmasq-base, p-cpe:/a:debian:debian_linux:dnsmasq-utils, p-cpe:/a:debian:debian_linux:dnsmasq-base-lua

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/10/2026

Vulnerability Publication Date: 5/11/2026

Reference Information

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

IAVA: 2026-A-0450

Detections

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