Windows DHCP Server: Remote code execution via race condition
Summary
The Windows DHCP Server role in Windows Server 2016, 2019, 2022 and 2025 contains a time-of-check time-of-use race condition (CWE-367) and a heap-based buffer overflow (CWE-122). According to the CVSS vector (7.5, high attack complexity, low privileges), an authorized attacker on the network may be able to execute code on the server. Microsoft rates exploit maturity as Unproven at publication.
Affected
- Windows Server 2016 and 2016 (Server Core installation): 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 and 2019 (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 2025 (Server Core installation): 10.0.26100.0 to before 10.0.26100.33822
Fixed in
- Windows Server 2016 (incl. Server Core): build 10.0.14393.9688 or later
- Windows Server 2019 (incl. Server Core): build 10.0.17763.9487 or later
- Windows Server 2022: build 10.0.20348.5870 or later
- Windows Server 2025 (incl. Server Core): build 10.0.26100.33822 or later
- KB number: Unknown.
Workaround
Unknown. No Microsoft workaround was found in the sources reviewed.
Exploitation
- Microsoft rates exploit maturity as Unproven (E:U), meaning no exploit code is known at publication.
- CISA SSVC: exploitation none, not automatable, total technical impact.
- No public proof of concept found. Exploitation in the wild: Unknown.
Our recommendation
- Install the November 2026 security update on all affected Windows DHCP servers, starting with servers that serve multiple network segments.
- Until patched, restrict access to DHCP (UDP 67/68) to authorized networks using network segmentation and firewall rules.
- Do not expose DHCP servers to the internet.
- Monitor DHCP servers for crashes, unexpected processes and configuration changes.
- Verify the product list and fixes in the MSRC advisory before rollout.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Windows DHCP 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: CVE-2026-88216 msrc.microsoft.com
- CVE Record CVE-2026-88216 (CVE Program) www.cve.org
- Strix: CVE-2026-88216 (third-party) www.strix.ai
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- PT-2026-112085 (related DHCP issue) vulners.com
- BDU:2026-16536 (related DHCP issue) vulners.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, 05:07.
Original description (NVD)
Time-of-check time-of-use (toctou) race condition in Windows DHCP Server allows an authorized attacker to execute code 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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