Microsoft Windows Shell: Double free allows local privilege escalation
Summary
A double free vulnerability (CWE-415) in the Windows Shell component allows a locally authorized attacker to elevate privileges. The CVSS base score is 7.8 according to the CNA record. Exploitation requires local access with low privileges and no user interaction, so the risk is mainly for shared workstations, terminal servers and other hosts where users already have a foothold.
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
- Windows 10 1607 and Server 2016: 10.0.14393.9688 or later
- Windows 10 1809 and Server 2019: 10.0.17763.9487 or later
- Windows 10 21H2: 10.0.19044.7846 or later
- Other listed versions: Unknown. Check the MSRC Security Update Guide for the fixed builds and KB numbers.
Workaround
Unknown.
Exploitation
- Exploited in the wild: no evidence found.
- Public proof of concept: none found.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Not listed in CISA KEV as far as checked.
Our recommendation
- Install the November 2026 cumulative update, or a later one, on all affected Windows systems. Confirm the fixed builds in the MSRC advisory first.
- Prioritise shared workstations, RDP and terminal servers, and unpatched Windows 10 systems.
- Restrict local logon to trusted users and limit code execution on shared hosts as an interim measure.
- Re-check the status once MSRC publishes the full table and exploit maturity.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Shell
- 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
- CVE.org record (Microsoft CNA) www.cve.org
- MSRC Security Update Guide msrc.microsoft.com
- VulDB entry 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, 03:52.
Original description (NVD)
Double free in Windows Shell 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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