Microsoft Windows WMI: Heap-based buffer overflow enables local privilege escalation
Summary
A heap-based buffer overflow in Windows Management Instrumentation (WMI) affects multiple supported Windows 10, Windows 11 and Windows Server versions. An authorized local attacker with a low-privilege account can exploit it to elevate privileges, which can lead to full control of the affected system. No user interaction is required, but the attacker must already have local access.
Affected
- Windows 10 Version 1607 (builds before 10.0.14393.9688)
- Windows 10 Version 1809 (builds before 10.0.17763.9487)
- Windows 10 Version 21H2 (builds before 10.0.19044.7846)
- Windows 10 Version 22H2 (builds before 10.0.19045.7846)
- Windows 11 Version 23H2 (builds before 10.0.22631.7711)
- Windows 11 Version 24H2 (builds before 10.0.26100.9974)
- Windows 11 Version 25H2 (builds before 10.0.26200.9974)
- Windows 11 Version 26H1 (builds before 10.0.28000.3501)
- Windows 11 Version 26H2 (builds before 10.0.26300.9974)
- Windows Server 2016, including Server Core (builds before 10.0.14393.9688)
- Windows Server 2019, including Server Core (builds before 10.0.17763.9487)
- Windows Server 2022 (builds before 10.0.20348.5870)
Fixed in
- Install the Microsoft security update from November 2026 for each affected build.
- Exact KB numbers per build: check the MSRC advisory, as they could not be verified here.
Workaround
Unknown. No vendor workaround or mitigation has been identified.
Exploitation
- No exploitation in the wild reported.
- No public proof-of-concept exploit found.
- CISA SSVC assessment: exploitation none, not automatable, total technical impact.
Our recommendation
- Patch affected systems in the November 2026 update cycle, starting with shared workstations, Remote Desktop and terminal servers, and other multi-user systems.
- Check whether Windows 10 1607 and 1809 are still supported by Microsoft and plan upgrades if they are not.
- Review local administrator rights and account hygiene to limit the risk of local escalation.
- Verify the exact fixed builds and KB numbers on the MSRC advisory before rollout.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Management Instrumentation
- 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, KB5131096, KB5131090, KB5131087, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-105503 msrc.microsoft.com
- CVE Record CVE-2026-105503 www.cve.org
- VulDB entry 434541 vuldb.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, 04:36.
Original description (NVD)
Heap-based buffer overflow in Windows Management Instrumentation allows an authorized attacker to elevate privileges locally.
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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