Windows Server DNS Server: Denial of service via out-of-bounds read
Summary
The DNS Server role in Windows Server 2016, 2019, 2022 and 2025 contains an out-of-bounds read flaw (CWE-125). An unauthenticated attacker on the network can cause a denial of service of the DNS service. Attack complexity is high, and the impact is limited to availability (CVSS 5.9, Medium). Exploitation is not known.
Affected
- Windows Server 2016 and Server Core installation: 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 and Server Core installation: 10.0.17763.0 to before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 to before 10.0.20348.5870
- Windows Server 2025 and Server Core installation: 10.0.26100.0 to before 10.0.26100.33822
Fixed in
- Windows Server 2016 (incl. Server Core): 10.0.14393.9688 or later
- Windows Server 2019 (incl. Server Core): 10.0.17763.9487 or later
- Windows Server 2022: 10.0.20348.5870 or later
- Windows Server 2025 (incl. Server Core): 10.0.26100.33822 or later
Build numbers are taken from the CVE record and should be checked against the MSRC advisory.
Workaround
Unknown. No vendor workaround is documented.
Exploitation
- Not known to be exploited in the wild.
- Rapid7 lists Microsoft's exploitability assessment as Exploitation Less Likely.
- CISA SSVC: exploitation none, not automatable, partial technical impact.
- No public proof of concept found.
Our recommendation
- Patch DNS servers, especially Windows Server 2016 and 2019, in the next maintenance window.
- Prioritise internet-facing or broadly reachable DNS servers.
- Check whether DNS is publicly reachable and restrict it if not needed.
- Until patched, restrict recursion and query access to required clients only.
- Monitor DNS service availability for crashes or restarts.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Denial of service – Role: DNS Server
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131291, KB5131085, KB5131090, KB5131080, KB5131077
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center advisory CVE-2026-96975 msrc.microsoft.com
- CVE Record CVE-2026-96975 www.cve.org
- Strix CVE-2026-96975 www.strix.ai
- OffSeq Radar CVE-2026-96975 radar.offseq.com
- Rapid7 Patch Tuesday November 2026 www.rapid7.com
- GBHackers Microsoft November 2026 Patch Tuesday gbhackers.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, 15:07.
Original description (NVD)
Out-of-bounds read in DNS Server 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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