CVE-2026-70166 Windows DNS Denial of Service Vulnerability
An authorized attacker can cause a denial of service in Windows DNS via an out-of-bounds read, affecting Windows OS and Server installations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-70166?
CVE-2026-70166 is a medium-severity denial of service vulnerability in Microsoft Windows 10 1607, published on 13 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Out-of-bounds read in Windows DNS allows an authorized attacker to deny service over a network.
Weakness: CWE-125
Which versions are affected by CVE-2026-70166?
It affects 7 products.
Products include Microsoft Windows 10 1607, Microsoft Windows 10 1809, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows Server 2022 and 1 more.
How do I fix CVE-2026-70166?
No fix has been published for CVE-2026-70166 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-70166 being exploited?
There is no known exploitation of CVE-2026-70166 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 10 1607
- CVE-2026-33824 Microsoft Internet Key Exchange (IKE) Service Extensions Double Free
- CVE-2026-21510 Microsoft Windows Shell Protection Mechanism Failure
- CVE-2026-21513 Microsoft MSHTML Framework Protection Mechanism Failure
- CVE-2023-32049 Microsoft Windows Defender SmartScreen Security Feature Bypass
- CVE-2023-29360 Microsoft Streaming Service Untrusted Pointer Dereference
Sources
Also known as GHSA-cgj9-9xx5-69p6.