Windows 11: Heap-based buffer overflow in Windows MIDI Service Module
Summary
A heap-based buffer overflow in the Windows MIDI Service Module of Windows 11 allows an authorized local user to elevate privileges. The attacker needs an existing logon on the affected machine and no user interaction is required. Successful exploitation gives the attacker full control over confidentiality, integrity and availability of the system.
Affected
- Windows 11 Version 24H2: 10.0.26100.0 to below 10.0.26100.9711
- Windows 11 Version 25H2: 10.0.26200.0 to below 10.0.26200.9711
- Windows 11 Version 26H1: 10.0.28000.0 to below 10.0.28000.3231
- Windows 11 Version 26H2: 10.0.26300.0 to below 10.0.26300.9711
Fixed in
- Install the October 2026 cumulative update for the affected Windows 11 version (builds listed above or higher)
- Update package names per third-party sources, not yet verified against MSRC: KB5127648 (24H2, 25H2, 26H2) and KB5127646 (26H1)
Workaround
Unknown.
Exploitation
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total
- Not listed in CISA KEV
- EPSS score 0.00318
- No public proof-of-concept found (this does not prove that none exists)
Our recommendation
- Install the October 2026 cumulative update on all affected Windows 11 systems, including 25H2, 26H1 and 26H2, not only 24H2
- Confirm the build numbers and KB numbers in the Microsoft Security Update Guide before the change window
- Prioritize shared workstations, terminal servers and endpoints where staff or contractors have local logons
- Monitor for unusual privilege escalation on endpoints until patched
Information from Microsoft (Patch Tuesday October 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-83828 msrc.microsoft.com
- OpenCVE: CVE-2026-83828 (CISA SSVC data) app.opencve.io
- Strix.ai: CVE-2026-83828 www.strix.ai
- Vulners: CVE-2026-83828 (CVE list) vulners.com
- Vulners: CVE-2026-83828 (NVD) vulners.com
- Vulners: CVE-2026-83828 (Rapid7, EPSS) vulners.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 2 Nov 2026, 02:55.
Original description (NVD)
Heap-based buffer overflow in Windows MIDI Service Module 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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