medium · CVSS 5.3

CVE-2026-93007

Dnsmasq: dnsmasq: tcp/53 child-slot exhaustion starves dnssec validation

Published 29 Oct 2026 · Source updated 6 Nov 2026 · Retrieved 2026-11-06 02:52 UTC

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What happened?

A flaw was found in dnsmasq. The TCP DNS service uses a small fixed pool of child processes and does not set a receive timeout on client connections. A remote attacker can open idle TCP connections to port 53 and occupy the entire pool, preventing new TCP DNS connections and DNSSEC validation that requires TCP fallback. UDP DNS resolution continues, and occupied slots are released after a fixed lifetime.

Description supplied by CVE Program. Formatting is simplified; follow the original advisory for full details.

Affected software and versions

Source-provided software and version information
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.

CISA data retrieved 2026-11-06 16:38 UTC. Check CISA ↗

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.

Sources and remediation references

This public advisory does not determine whether a particular server is affected. Records are refreshed as sources change; verify urgent decisions against the original advisory.

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