CVE-2026-3238 Samba: denial of service against ad dc wins server
An unauthenticated remote attacker can crash the Samba WINS service on Active Directory Domain Controllers via crafted UDP packets.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-3238?
CVE-2026-3238 is a high-severity vulnerability in Red Hat Enterprise Linux 10, published on 8 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A flaw was found in Samba’s WINS server component when running as an Active Directory Domain Controller. The WINS protocol handlers for certain request types did not properly validate incoming packets, allowing an unauthenticated remote attacker to trigger a NULL pointer dereference and crash the WINS service using specially crafted UDP packets.
Weakness: CWE-476
Which versions are affected by CVE-2026-3238?
How do I fix CVE-2026-3238?
Apply the vendor's patch.
Is CVE-2026-3238 being exploited?
There is no known exploitation of CVE-2026-3238 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-3238, AZL-89519, CLSA-2026-1782159797, DEBIAN-CVE-2026-3238, ECHO-4f6e-0017-81fd, GHSA-gpff-px68-36rh and 1 more.