Microsoft Windows Desktop Window Manager: Elevation of privilege via heap overflow
Summary
A heap-based buffer overflow in the Windows Desktop Window Manager (DWM) allows an authorized local user to elevate privileges. An attacker needs an existing low-privilege foothold on the machine, such as a phished user account or a malicious application. Successful exploitation would give the attacker high confidentiality, integrity and availability impact on the system.
Affected
- 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 (per CVE record)
- Windows 11 version 26H1: 10.0.28000.0 before 10.0.28000.3501 (per CVE record)
- Windows 11 version 26H2: 10.0.26300.0 before 10.0.26300.9974 (per CVE record)
- Windows Server 2025 (including Server Core): 10.0.26100.0 before 10.0.26100.33822 (per CVE record; build number differs from 24H2 and is unverified)
- Windows 10 and older Server editions: Unknown.
Fixed in
- Windows 11 23H2: build 10.0.22631.7711 or later
- Windows 11 24H2: build 10.0.26100.9974 or later
- Windows 11 25H2, 26H1, 26H2 and Windows Server 2025: fixed builds as listed above, to be verified on the MSRC page
- Cumulative update of November 2026 (Patch Tuesday, 10 Nov 2026)
Workaround
No vendor workaround known.
Exploitation
- No evidence of exploitation in the wild found at the time of research.
- No public proof of concept found.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- The CVSS exploit maturity is 'Unproven' (E:U). This is a scoring field, not a confirmation.
- The exploited zero-day of the November 2026 release is named as an Outlook issue in some reports; sources disagree on its CVE ID, so this could not be fully ruled out.
Our recommendation
- Install the November 2026 cumulative update on all affected Windows 11 and Windows Server 2025 systems, prioritising shared, admin-heavy and remote-user endpoints.
- Verify the fixed build for each Windows version on the MSRC Security Update Guide before rollout, because some build numbers are unverified.
- Enforce least privilege for daily users and keep EDR and timely patching in place to limit the impact of a local foothold.
- Monitor endpoints for suspicious privilege escalation activity.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Response Center: CVE-2026-96103 msrc.microsoft.com
- CVE.org Record CVE-2026-96103 www.cve.org
- Strix: CVE-2026-96103 (third-party mirror, unverified) www.strix.ai
- BleepingComputer: Microsoft 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, 02:36.
Original description (NVD)
Heap-based buffer overflow in Desktop Window Manager 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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