CVE-2026-4891 CVE-2026-4891
Remote attackers can cause denial of service in dnsmasq via crafted DNS packets exploiting a heap-based out-of-bounds read in DNSSEC validation.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-4891?
CVE-2026-4891 is a medium-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 heap-based out-of-bounds read vulnerability in the DNSSEC validation of dnsmasq allows remote attackers to cause a denial of service via a crafted DNS packet.
Weakness: CWE-125
Which versions are affected by CVE-2026-4891?
How do I fix CVE-2026-4891?
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-2026-4891 being exploited?
There is no known exploitation of CVE-2026-4891 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-4891, AZL-86757, BELL-CVE-2026-4891, CLEANSTART-2026-BB03261, DEBIAN-CVE-2026-4891, GHSA-2qp9-xr4x-2cr9 and 1 more.