Microsoft Windows Win32k: Information disclosure via uninitialized resource
Summary
Microsoft Windows Win32k, the kernel-mode graphics subsystem, contains a flaw in which an uninitialized resource is used. A local attacker with a low-privilege account can read kernel memory contents, which may be exposed to the attacker. The vulnerability affects confidentiality only, and no public exploit code is known. The information could support a later privilege escalation chain.
Affected
- Windows 10 Version 1607 before 10.0.14393.9688
- Windows 10 Version 1809 before 10.0.17763.9487
- Windows 10 Version 21H2 before 10.0.19044.7846
- Windows 10 Version 22H2 before 10.0.19045.7846
- Windows 11 Version 23H2 before 10.0.22631.7711
- Windows 11 Version 24H2 before 10.0.26100.9974 (CNA record also lists 10.0.26100.33822; to be verified)
- Windows 11 Version 25H2 before 10.0.26200.9974
- Windows 11 Version 26H1 before 10.0.28000.3501
- Windows 11 Version 26H2 before 10.0.26300.9974
- Windows Server 2016 (including Server Core) before 10.0.14393.9688
- Windows Server 2019 (including Server Core) before 10.0.17763.9487
- Windows Server 2022 before 10.0.20348.5870 (per CNA record; not yet confirmed by a second source)
- Windows Server 2025: Unknown.
Fixed in
- Install the November 2026 cumulative update for the affected Windows version.
- Fixed builds as listed above; verify build numbers against the MSRC advisory.
Workaround
Unknown. No vendor workaround has been found.
Exploitation
- Not publicly disclosed.
- CNA vector includes E:U (exploit code maturity: Unproven); no public exploit code is known.
- Not listed in CISA KEV; CISA SSVC: exploitation none, not automatable.
- Rapid7 lists it as Exploitation Less Likely.
Our recommendation
- Install the November 2026 Windows cumulative update on all affected systems, with priority on multi-user systems, terminal servers and Windows Server 2019 hosts.
- Verify the installed build numbers against the MSRC advisory.
- Restrict local logon and limit low-privilege accounts on shared systems.
- Monitor for suspicious local activity on systems where this risk is relevant.
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
- Microsoft Security Response Center advisory (not verified) msrc.microsoft.com
- CVE.org CVE record (CNA: Microsoft) www.cve.org
- Rapid7 Patch Tuesday November 2026 www.rapid7.com
- Senserva KB5131087 (Windows 11 23H2) senserva.com
- Senserva KB5131085 (Windows 10 1809, Server 2019) senserva.com
- Strix.ai CVE-2026-119825 (secondary source) 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, 16:44.
Original description (NVD)
Use of uninitialized resource 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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