CVE-2026-93007Dnsmasq: dnsmasq: tcp/53 child-slot exhaustion starves dnssec validation
- 5.3MediumCVSS base score
- 0.43%Exploitation in 30 daysEPSS · top 63% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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
ID reserved
By redhat
- 42 days later
· 42 days later
Published
- 8 days later
· 8 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| redhatCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
| NVDNVD · Awaiting Analysis | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 0.43% · top 63% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.3.
Affected products
Red Hat · Red Hat Ceph Storage 9
All versions: affected
Red Hat · Red Hat Enterprise Linux 10
All versions: affected
Red Hat · Red Hat Enterprise Linux 6
All versions: affected
Red Hat · Red Hat Enterprise Linux 7
All versions: affected
Red Hat · Red Hat Enterprise Linux 8
All versions: affected
Red Hat · Red Hat Enterprise Linux 9
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 4
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 5
All versions: affected
Red Hat · Red Hat OpenShift Container Platform 5
All versions: affected
Red Hat · Red Hat OpenStack Platform 13 (Queens)
All versions: affected
Red Hat · Red Hat OpenStack Platform 18.0
All versions: affected
What to do
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.
References
References2
- https://access.redhat.com/security/cve/CVE-2026-93007 (opens in a new tab)vdb-entryx_refsource_REDHAT
- RHBZ#2536076 (opens in a new tab)issue-trackingx_refsource_REDHAT
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-112790 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-93007)Record last updated .