Windows Win32k: Information disclosure via TOCTOU race condition
Summary
A time-of-check time-of-use (TOCTOU) race condition in the Windows Win32k kernel subsystem allows an authorized local attacker to disclose information. According to MSRC, an attacker could obtain touch input intended for another window in the same user session. Exploitation requires a local account with low privileges and a high-complexity race condition, so the flaw is not remotely exploitable. Microsoft has released fixes, and no public proof of concept or exploitation is known.
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 incl. Server Core (10.0.14393.0 before 10.0.14393.9688)
- Windows Server 2019 incl. 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
- Install the Microsoft security update for November 2026 (Patch Tuesday) or a later cumulative update for the affected build.
- Fixed builds per CVE record: see the list above (first build not affected).
- KB numbers: check the MSRC Security Update Guide for each product.
Workaround
Unknown. No workaround is documented; apply the security update.
Exploitation
- Exploited in the wild: no evidence found.
- Public proof of concept: none found.
- CISA KEV: not verified.
- CISA SSVC: exploitation none, not automatable, partial technical impact.
Our recommendation
- Patch all affected Windows 10, 11 and Server systems in the next monthly patch cycle.
- Prioritise multi-user systems such as terminal servers, RDS hosts and shared workstations.
- Identify Windows 10 1607, 1809 and 21H2 systems still in use and check their Extended Security Updates (ESU) enrolment.
- Verify the product list on the MSRC page before rollout.
Information from Microsoft (Patch Tuesday November 2026)
- Severity (Microsoft)
- Important
- Impact
- Information disclosure – Windows Win32K
- 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
- MSRC Security Update Guide: CVE-2026-119910 msrc.microsoft.com
- CVE.org record CVE-2026-119910 www.cve.org
- Rapid7 Patch Tuesday, November 2026 www.rapid7.com
- BleepingComputer: November 2026 Patch Tuesday www.bleepingcomputer.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, 20:17.
Original description (NVD)
Time-of-check time-of-use (toctou) race condition in Windows Win32K allows an authorized attacker to disclose information 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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