CVE-2026-5172 CVE-2026-5172
An attacker can crash the dnsmasq server by sending a malformed DNS response that triggers a heap out-of-bounds read.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-5172?
CVE-2026-5172 is a high-severity memory corruption vulnerability in dnsmasq, published on 11 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record’s end.
Weakness: CWE-125
Which versions are affected by CVE-2026-5172?
How do I fix CVE-2026-5172?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-5172 being exploited?
There is no known exploitation of CVE-2026-5172 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as ALPINE-CVE-2026-5172, AZL-86766, BELL-CVE-2026-5172, CLEANSTART-2026-OG08505, DEBIAN-CVE-2026-5172, GHSA-57vp-ffx7-7gm6 and 1 more.