Windows Event Collector Service: Double free allows local privilege escalation
Summary
A double free vulnerability (CWE-415) in the Windows Event Collector Service allows an authorized local attacker to elevate privileges. The CVSS vector requires local access, high attack complexity, low privileges and no user interaction, so an attacker must already have a foothold on the host. The impact is rated high for confidentiality, integrity and availability. Microsoft's own rating indicates no public exploit code at publication, but this is not independent evidence.
Affected
- Windows 10 Version 1607: 10.0.14393.0 before 10.0.14393.9688
- Windows 10 Version 1809: 10.0.17763.0 before 10.0.17763.9487
- Windows 10 Version 21H2: 10.0.19044.0 before 10.0.19044.7846
- Windows 10 Version 22H2: 10.0.19045.0 before 10.0.19045.7846
- Windows 11 Version 23H2: 10.0.22631.0 before 10.0.22631.7711
- Windows 11 Version 24H2: 10.0.26100.0 before 10.0.26100.9974
- Windows 11 Version 25H2: 10.0.26200.0 before 10.0.26200.9974
- Windows 11 Version 26H1: 10.0.28000.0 before 10.0.28000.3501
- Windows 11 Version 26H2: 10.0.26300.0 before 10.0.26300.9974
- Windows Server 2016 (including Server Core): 10.0.14393.0 before 10.0.14393.9688
- Windows Server 2019 (including Server Core): 10.0.17763.0 before 10.0.17763.9487
- Windows Server 2022: 10.0.20348.0 before 10.0.20348.5870
Fixed in
- Build numbers at or above the listed 'before' values, released with the November 2026 Patch Tuesday.
- Exact KB numbers: see the Microsoft Security Update Guide.
Workaround
Unknown.
- No vendor-documented workaround found.
Exploitation
- Microsoft rates exploit code maturity as unproven (E:U) and report confidence as confirmed (RC:C).
- CISA SSVC: exploitation none, automatable no, technical impact total.
- No evidence found of CISA KEV listing, public proof-of-concept code or in-the-wild exploitation for this CVE.
Our recommendation
- Patch in the regular monthly cycle; prioritise Windows servers where the Windows Event Collector service runs.
- Check with PowerShell or services.msc whether the service is in use (Get-Service Wecsvc).
- If the service is not needed, stop and disable it until patched (analyst suggestion, not vendor-confirmed).
- Monitor for exploitation reports and review local accounts and privileged access.
- Verify the patch level of the affected systems after installation.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Event Collector Service
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5131085, KB5131090, KB5131096, KB5131080, KB5131077, KB5132061
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-112796 msrc.microsoft.com
- CVE Record CVE-2026-112796 www.cve.org
- Rapid7: Patch Tuesday November 2026 www.rapid7.com
- Talos: Microsoft Patch Tuesday November 2026 blog.talosintelligence.com
- strix.ai: CVE-2026-112796 (unverified aggregator) www.strix.ai
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, 09:14.
Original description (NVD)
Double free in Windows Event Collector Service 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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