Dnsmasq: dnsmasq: tftp prefetch cache keyed on stale heap pointer serves wrong file content
Summary
| CVE | CVE-2026-93006 |
|---|---|
| State | PUBLISHED |
| Assigner | redhat |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-29 13:17:15 UTC |
| Updated | 2026-10-30 02:17:10 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 6.8 MEDIUM from [email protected]
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Problem Types: CWE-672 | CWE-672 Operation on a Resource after Expiration or Release
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 6.8 | MEDIUM | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 6.8 | MEDIUM | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
AdjacentAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
NoneCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| bugzilla.redhat.com/show_bug.cgi | [email protected] | bugzilla.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-93006 | [email protected] | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Red Hat would like to thank Shubham Raj (Causal Security) for reporting this issue. (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-14T00:00:00.000Z | Reported to Red Hat. |
| CNA | 2026-10-28T09:32:00.000Z | Made public. |
Workarounds
CNA: 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.
There are currently no legacy QID mappings associated with this CVE.