Windows Deployment Services: Use-after-free leads to remote code execution
Summary
Windows Deployment Services (WDS), a Windows Server role, contains a use-after-free flaw (CWE-416). An unauthorized attacker on the network could execute code on an affected server. The CVSS vector rates attack complexity as high and assumes no privileges and no user interaction, but a vendor patch review suggests a low-privileged account may be needed; this is not yet confirmed by Microsoft.
Affected
- Windows Server 2016 and Windows Server 2016 (Server Core installation): 10.0.14393.0 to before 10.0.14393.9688
- Windows Server 2019 and Windows Server 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 Windows Server 2025 (Server Core installation): 10.0.26100.0 to before 10.0.26100.33822
Fixed in
- November 2026 security update. KB number: Unknown.
- Install the November 2026 update or a later build that is at or above the fixed build numbers listed above.
Workaround
Unknown. No CVE-specific workaround has been published.
- Until patched, restrict network access to WDS and TFTP services and disable the WDS role where it is not required. Microsoft has not confirmed this measure for this CVE.
Exploitation
- No known exploitation in the wild at the time of analysis.
- No public proof of concept is known.
- CISA SSVC: exploitation none, not automatable, technical impact total.
- Exploit code maturity: unproven (E:U).
Our recommendation
- Inventory all WDS servers, including lab and test systems.
- Install the November 2026 security update on all affected servers and verify the build number.
- Block WDS and TFTP traffic from untrusted networks and disable the role where it is not needed.
- Monitor for unusual deployment or PXE traffic.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Critical
- Impact
- Remote code execution – Windows Deployment Services
- 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 Update Guide: CVE-2026-119951 msrc.microsoft.com
- CVE.org record CVE-2026-119951 www.cve.org
- Strix: CVE-2026-119951 www.strix.ai
- Zero Day Initiative: November 2026 security update review www.zerodayinitiative.com
- Qualys: Microsoft Patch Tuesday November 2026 review blog.qualys.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, 01:41.
Original description (NVD)
Use after free in Windows Deployment Services 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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