DEBIAN-CVE-2026-93008: Medium severity debian/dnsmasq vulnerability
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.
Affected Software
Event History
Frequently Asked Questions
Which dnsmasq deployments are exposed to this issue?
Split-DNS deployments that route some domains to a specific upstream resolver are exposed when that upstream can be controlled by an attacker. The issue depends on dnsmasq following a CNAME response from that upstream.
What does an attacker need to exploit the flaw?
The attacker needs control of an upstream DNS server used for a routed domain and must provide a response containing a CNAME. No client interaction or authenticated privileges are required.
What is the practical impact of successful exploitation?
An attacker can cause dnsmasq to cache records for unrelated names and later return attacker-selected addresses to clients querying those names. The stated impact is integrity-related; confidentiality and availability impact are not indicated.