Windows DNS: Memory leak allows network denial of service
Summary
Microsoft Windows DNS does not release memory after its effective lifetime (CWE-401). An unauthenticated attacker on the network can trigger memory exhaustion and cause a denial of service on the affected DNS service. The CVSS vector indicates availability impact only, with no code execution or data disclosure. No exploitation in the wild or public proof of concept is known at the time of writing.
Affected
- Windows 11 Version 23H2: before 10.0.22631.7711
- Windows 11 Version 24H2: before 10.0.26100.9974
- Windows 11 Version 25H2: before 10.0.26200.9974
- Windows 11 Version 26H1: before 10.0.28000.3501
- Windows 11 Version 26H2: before 10.0.26300.9974
- Windows Server 2025 (including Server Core): before 10.0.26100.33822
- Windows Server 2016, 2019 and 2022: Unknown.
Fixed in
- Install the Microsoft security update for the respective version. The fixed builds are the builds listed above (for example 10.0.22631.7711 or 10.0.26100.33822).
Workaround
Unknown. No vendor workaround identified; apply the security update.
Exploitation
- Not known to be exploited in the wild (CISA SSVC: exploitation none).
- CISA SSVC: automatable yes, technical impact partial.
- No public proof of concept found.
Our recommendation
- Identify systems with the Windows DNS Server role (for example with Get-WindowsFeature DNS on servers).
- Install the Microsoft security update for the affected builds, starting with internet-facing DNS servers and domain controllers.
- Restrict DNS server exposure to untrusted networks and monitor memory usage on DNS servers.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-96176 msrc.microsoft.com
- CVE Record CVE-2026-96176 www.cve.org
- Strix: CVE-2026-96176 www.strix.ai
- OffSeq Radar: CVE-2026-96176 radar.offseq.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 05:03.
Original description (NVD)
Missing release of memory after effective lifetime in Windows DNS allows an unauthorized attacker to deny service over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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