CVE-2026-93008 Dnsmasq: dnsmasq: out-of-bailiwick cache injection through cname chase in split-dns configurations

Description

A flaw was found in dnsmasq. When following a CNAME in a DNS response, the resolver can cache records for the CNAME target without checking that those records belong to the responding server's authorized zone. In split-DNS deployments that send some domains to a specific upstream, an attacker who controls that upstream can inject cache entries for unrelated names. Later clients may then receive attacker-chosen addresses for those names.

Exploitable remotely over the network, without an account and without any user action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Network

Attack complexity

High

Privileges required

None

Interaction

None

Scope

Changed

Confidentiality

None

Integrity

High

Availability

None

Affected products and versions