# CVE-2026-93006: Dnsmasq: dnsmasq: tftp prefetch cache keyed on stale heap pointer serves wrong file content

Status: published. Published: 2026-10-29. Updated: 2026-11-02.

A flaw was found in dnsmasq. The TFTP server can serve the wrong file contents because a recently used transfer cache is not invalidated when a transfer finishes. An attacker on the local network who can request a TFTP file may cause a later client to receive previously cached data instead of the requested file. In PXE network-boot environments this can substitute attacker-chosen boot content for a victim machine.

## Remediation

- workaround: The following measures reduce risk:

1. If TFTP is not required, do not enable it. Remove --enable-tftp from the dnsmasq configuration.
2. If TFTP is required, restrict it with --tftp-interface=<interface> and avoid running TFTP-only instances that serve untrusted clients on the same network.
3. Compile without TFTP support using COPTS=-DNO_TFTP if TFTP is not needed. (source: CNA: redhat)

## Affected products and versions

- Red Hat / Red Hat Ceph Storage 9 (rhceph/alloy-rhel10): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift4/ose-baremetal-runtimecfg-rhel8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift4/ose-baremetal-runtimecfg-rhel9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift5/ose-baremetal-runtimecfg-rhel9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 5 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenStack Platform 13 (Queens) (dnsmasq): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenStack Platform 18.0 (rhoso-operators/infra-rhel9-operator): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.8 (medium); CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.30% as of 2026-11-02; percentile 22.98%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-672

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/security/cve/CVE-2026-93006 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2536075 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2026-93006; retrieved 2026-11-02; source updated 2026-11-02

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-93006; retrieved 2026-11-02; source updated Not reported

Revision: c354d717100e4cb74732a517e40d609407c90382af2208274ff83fe067d01b24

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