Windows DHCP Server: Out-of-bounds read leading to remote code execution
Summary
An out-of-bounds read in the Windows DHCP Server role allows an unauthenticated attacker on the network to execute code, according to the official CVE record. The CVSS 3.1 base score is 9.8 (critical), and the vector requires no privileges and no user interaction. Windows Server 2016, 2019, 2022 and 2025 are affected below the builds listed in the CVE record. Exploitation status and the exact attack prerequisites are not yet confirmed.
Affected
- Windows Server 2016 (incl. Server Core): builds 10.0.14393.0 to below 10.0.14393.9688
- Windows Server 2019 (incl. Server Core): builds 10.0.17763.0 to below 10.0.17763.9487
- Windows Server 2022: builds 10.0.20348.0 to below 10.0.20348.5870
- Windows Server 2025 (incl. Server Core): builds 10.0.26100.0 to below 10.0.26100.33822
Fixed in
Unknown. The fixed builds and KB numbers are not confirmed in the sources. Systems at or above the upper build limits listed above are not affected per the CVE record; verify the KB numbers in the MSRC entry.
Workaround
Unknown. No vendor-specific workaround has been identified.
Exploitation
- No public exploitation reported at the time of writing.
- No CISA KEV entry found.
- No public proof of concept found.
Our recommendation
- Identify all hosts running the DHCP Server role, including domain controllers and file servers.
- Install the Microsoft security update for the affected Windows Server versions as soon as the KB numbers are confirmed in the MSRC entry.
- Restrict DHCP access to the internal network and isolate guest and IoT segments.
- Monitor DHCP servers for abnormal activity until patched and check NVD and CISA KEV for updates.
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-2026-88243 msrc.microsoft.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, 20:34.
Original description (NVD)
Out-of-bounds read in Windows DHCP Server allows an unauthorized 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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