CVE-2026-93008
Dnsmasq: dnsmasq: out-of-bailiwick cache injection through cname chase in split-dns configurations
What happened?
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 and versions
| Software | Version information | Fixed version |
|---|---|---|
| rhceph/alloy-rhel10Red Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| openshift4/ose-baremetal-runtimecfg-rhel8Red Hat | Default status: affected | See vendor advisory |
| openshift4/ose-baremetal-runtimecfg-rhel9Red Hat | Default status: affected | See vendor advisory |
| openshift/ose-rhel-coreos-8Red Hat | Default status: affected | See vendor advisory |
| openshift/ose-rhel-coreos-9Red Hat | Default status: affected | See vendor advisory |
| openshift5/ose-baremetal-runtimecfg-rhel9Red Hat | Default status: affected | See vendor advisory |
| openshift/ose-rhel-coreos-9Red Hat | Default status: affected | See vendor advisory |
| dnsmasqRed Hat | Default status: affected | See vendor advisory |
| rhoso-operators/infra-rhel9-operatorRed Hat | Default status: affected | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.