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.
Published: 2026-10-29
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

Vendor Workaround

The following measures reduce risk: 1. Increase the TCP connection limit with --max-tcp-connections=<N> to raise the number of connections an attacker must hold. 2. Limit per-source TCP connections to port 53 with firewall rules, for example iptables connlimit on tcp/53. 3. Restrict which hosts can reach TCP port 53 if TCP DNS is not required from untrusted networks.

Tracking

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Advisories

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History

Fri, 30 Oct 2026 07:30:00 +0000

Type Values Removed Values Added
CPEs cpe:/a:redhat:openshift:5

Fri, 30 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Thu, 29 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 29 Oct 2026 13:00:00 +0000

Type Values Removed Values Added
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.
Title Dnsmasq: dnsmasq: tcp/53 child-slot exhaustion starves dnssec validation
First Time appeared Redhat
Redhat ceph Storage
Redhat enterprise Linux
Redhat openshift
Redhat openstack
Weaknesses CWE-400
CPEs cpe:/a:redhat:ceph_storage:9
cpe:/a:redhat:openshift:4
cpe:/a:redhat:openstack:13
cpe:/a:redhat:openstack:18.0
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat ceph Storage
Redhat enterprise Linux
Redhat openshift
Redhat openstack
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}


Subscriptions

Redhat Ceph Storage Enterprise Linux Openshift Openstack
cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-10-30T07:12:44.289Z

Reserved: 2026-09-17T14:35:34.562Z

Link: CVE-2026-93007

cve-icon Vulnrichment

Updated: 2026-10-29T15:43:45.711Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-29T13:17:15.890

Modified: 2026-10-30T08:17:00.560

Link: CVE-2026-93007

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-28T09:32:00Z

Links: CVE-2026-93007 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-29T16:30:14Z

Weaknesses