Windows DNS: Remote code execution through deserialization

Summary

A deserialization flaw in the Windows DNS component allows an unauthorized attacker to execute code over the network. Successful exploitation would have high impact on confidentiality, integrity and availability. The CVSS vector requires user interaction (UI:R), and the CVSS base score is 8.8 (High).

Affected

• Windows 10 Version 1607: 10.0.14393.0 to before 10.0.14393.9612
• Windows 10 Version 1809: 10.0.17763.0 to before 10.0.17763.9376
• Windows 10 Version 21H2: 10.0.19044.0 to before 10.0.19044.7807
• Windows 10 Version 22H2: 10.0.19045.0 to before 10.0.19045.7807
• Windows 11 Version 23H2: 10.0.22631.0 to before 10.0.22631.7652
• Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9711
• Windows 11 Version 25H2: 10.0.26200.0 to before 10.0.26200.9711
• Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3231
• Windows 11 Version 26H2: 10.0.26300.0 to before 10.0.26300.9711
• Windows Server 2012 (including Server Core): 6.2.9200.0 to before 6.2.9200.26434
• Windows Server 2012 R2 (including Server Core): 6.3.9600.0 to before 6.3.9600.23470
• Windows Server 2016: 10.0.14393.0 to before 10.0.14393.9612
• Whether the server role, the client or both are affected: Unknown.

Fixed in

• Install Microsoft's security update from the November 10, 2026 Patch Tuesday for each affected build.
• First fixed builds according to the CVE record: 10.0.14393.9612, 10.0.17763.9376, 10.0.19044.7807, 10.0.19045.7807, 10.0.22631.7652, 10.0.26100.9711, 10.0.26200.9711, 10.0.26300.9711, 10.0.28000.3231, 6.2.9200.26434, 6.3.9600.23470.
• Confirm the exact KB numbers and builds on the MSRC page before deployment.

Workaround

• Unknown. The sources list no vendor workaround.
• Do not expose DNS servers to the internet unless required.
• Restrict TCP/UDP 53 to known sources and limit recursion to internal clients.

Exploitation

• Not known to be exploited in the wild at the time of publication.
• CISA SSVC assessment: exploitation none, automatable no, technical impact total.
• No public proof of concept found. Status is unknown and should be re-checked.

Our recommendation

• Confirm the affected builds on the MSRC page, then patch Windows DNS servers and domain controllers first, followed by other Windows systems.
• Verify that DNS services are not reachable from the internet and restrict who can send queries.
• Monitor for exploitation and public proof-of-concept code over the coming weeks, since NVD analysis is pending.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide: CVE-2026-109463 msrc.microsoft.com
• CVE.org record CVE-2026-109463 (Microsoft as CNA) www.cve.org
• OffSeq threat radar: CVE-2026-109463 radar.offseq.com
• Strix: CVE-2026-109463 www.strix.ai
• 0patch: Micropatches for Windows DNS Server RCE 0patch.com
• Zero Day Initiative: November 2026 Security Update Review www.zerodayinitiative.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 10 Nov 2026, 23:56.