Executive brief
Windows DNS Server is a critical component that resolves domain names to IP addresses for corporate networks and internet connectivity. A use-after-free vulnerability allows an unauthenticated remote attacker to crash the DNS service, causing network clients to lose the ability to resolve hostnames and potentially disrupting business operations that depend on DNS availability.
Technical details
A use-after-free vulnerability exists in the Windows DNS service that allows an unauthenticated remote attacker to trigger a denial of service. The vulnerability is reachable over the network without requiring authentication or user interaction. By sending specially crafted DNS queries, an attacker can cause the DNS service to access memory that has been freed, leading to a crash or hang of the DNS Server process. This prevents legitimate DNS resolution for all clients depending on that DNS server.
Affected products
- Microsoft Windows DNS Server
Timeline
- 2026-09-08: disclosed