Dnsmasq: dnsmasq: tcp/53 child-slot exhaustion starves dnssec validation
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
Dnsmasq, a lightweight DNS forwarder and DHCP server widely used on Linux systems and network routers, is affected. A remote attacker could tie up its limited pool of TCP DNS connection handlers with idle connections, blocking new TCP DNS queries and DNSSEC validation that depends on TCP fallback, while UDP DNS resolution keeps working.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
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.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- rhceph/alloy-rhel10
Version range not reported
- dnsmasq
Version range not reported
- dnsmasq
Version range not reported
- dnsmasq
Version range not reported
- dnsmasq
Version range not reported
- dnsmasq
Version range not reported
- openshift4/ose-baremetal-runtimecfg-rhel8
Version range not reported
- openshift4/ose-baremetal-runtimecfg-rhel9
Version range not reported
- openshift/ose-rhel-coreos-8
Version range not reported
- openshift/ose-rhel-coreos-9
Version range not reported
- openshift5/ose-baremetal-runtimecfg-rhel9
Version range not reported
- openshift/ose-rhel-coreos-9
Version range not reported
- dnsmasq
Version range not reported
- rhoso-operators/infra-rhel9-operator
Version range not reported