Windows Broadcast DVR User Service: Heap-based buffer overflow in privilege escalation

Summary

The Windows Broadcast DVR User Service, used for Game Recordings and Live Broadcasts, contains a heap-based buffer overflow that allows privilege escalation. An attacker with a local, low-privileged account can exploit it to gain higher privileges, potentially full control of the machine. Exploitation requires high complexity and an existing foothold on the system; the flaw is not directly reachable from the internet.

Affected

• Microsoft Windows 10 Version 1809: 10.0.17763.0 to before 10.0.17763.9487
• Microsoft Windows 10 Version 21H2: 10.0.19044.0 to before 10.0.19044.7846
• Microsoft Windows 10 Version 22H2: 10.0.19045.0 to before 10.0.19045.7846
• Microsoft Windows 11 Version 23H2: 10.0.22631.0 to before 10.0.22631.7711 (per CVE record, secondary source unverified)
• Microsoft Windows 11 Version 24H2: 10.0.26100.0 to before 10.0.26100.9974 (per CVE record, secondary source unverified)
• Microsoft Windows 11 Version 25H2: 10.0.26200.0 to before 10.0.26200.9974 (per CVE record, secondary source unverified)
• Microsoft Windows 11 Version 26H1: 10.0.28000.0 to before 10.0.28000.3501 (per CVE record, secondary source unverified)
• Microsoft Windows 11 Version 26H2: 10.0.26300.0 to before 10.0.26300.9974 (per CVE record, secondary source unverified)
• Windows Server: Unknown.

Fixed in

• Windows 10 Version 1809: build 10.0.17763.9487 or later
• Windows 10 Version 21H2: build 10.0.19044.7846 or later
• Windows 10 Version 22H2: build 10.0.19045.7846 or later
• Windows 11 23H2, 24H2, 25H2, 26H1, 26H2: fixed builds per secondary source are 22631.7711, 26100.9974, 26200.9974, 28000.3501 and 26300.9974 (unverified)
• Fix is part of the November 2026 cumulative updates. KB number: Unknown.

Workaround

• No vendor-documented workaround found.
• Own suggestion (not vendor-confirmed): if Game DVR and broadcast features are not needed, disable the BcastDVRUserService. Test first on business systems.

Exploitation

• CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
• Exploit maturity in CVSS vector: E:U (unproven).
• No source found lists this CVE as exploited in the wild.
• No public proof of concept found.

Our recommendation

• Install the November 2026 cumulative update on all affected Windows 10 and Windows 11 systems and verify the build number afterwards.
• Prioritise workstations and shared PCs, RDS or terminal servers, and systems where untrusted users have local logons.
• Check the MSRC Security Update Guide for the KB mapping and the Windows Server status.
• If the Game DVR feature is not needed, consider disabling the service after testing.
• Monitor for unusual local privilege escalation activity.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Microsoft Security Update Guide: CVE-2026-94529 msrc.microsoft.com
• CVE Record CVE-2026-94529 www.cve.org
• Strix.ai: CVE-2026-94529 www.strix.ai
• BcastDVRUserService service description batcmd.com
• SmartPCUtilities: BcastDVRUserService www.smartpcutilities.com
• Rapid7: Patch Tuesday November 2026 www.rapid7.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, 08:07.