Microsoft Windows Media Foundation: Heap-based buffer overflow allows privilege escalation
Summary
A heap-based buffer overflow (CWE-122) in the Windows Media Foundation multimedia framework allows a local attacker to elevate privileges. Exploitation requires that the attacker already has a foothold on the system and that a user performs an action, for example by opening a malicious file. The CVSS base score is 7.8 (High), with high impact on confidentiality, integrity and availability.
Affected
- Windows 10 Version 1607 and Windows Server 2016: below 10.0.14393.9612
- Windows 10 Version 1809: below 10.0.17763.9376
- Windows 10 Version 21H2 and 22H2: below 10.0.19044.7807 and 10.0.19045.7807
- Windows 11 23H2: below 10.0.22631.7652
- Windows 11 24H2, 25H2 and Windows 11 26H2: see MSRC for the fixed builds
- Windows 11 26H1: below 10.0.28000.3231
- Windows Server 2012 and 2012 R2: below 6.2.9200.26434 and 6.3.9600.23470 respectively
- Please verify the affected versions against the MSRC advisory before use.
Fixed in
- Windows 10 Version 1607 and Windows Server 2016: KB5126868 (OS Build 14393.9612), released October 13, 2026
- Other versions: see the MSRC advisory for the fixed builds
Workaround
Unknown.
Exploitation
- Microsoft does not report exploitation at publication.
- Exploit code maturity is rated as unproven by Microsoft.
- No public proof-of-concept found.
- Tenable reports a KEV due date for a plugin that covers multiple CVEs; this CVE could not be confirmed in the CISA KEV catalog.
Our recommendation
- Install the October 2026 security update for each affected Windows version, starting with Windows 10 1607 and Server 2016 (KB5126868).
- Test the update first, as KB5126868 has known issues including audio device errors.
- Verify that endpoints are still under vendor support or ESU coverage.
- Restrict local logon and limit untrusted files and media on sensitive systems.
- Check the CISA KEV catalog directly for updates.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Microsoft Windows Media Foundation
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126835, KB5126836, KB5126868, KB5126651, KB5126657, KB5126655
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70131 msrc.microsoft.com
- Microsoft Support: KB5126868 Windows 10 1607 security update support.microsoft.com
- NVD via Vulners: CVE-2026-70131 vulners.com
- CNA data via Vulners: CVE-2026-70131 vulners.com
- Senserva: KB5126868 senserva.com
- Tenable plugin 365471 www.tenable.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, 04:07.
Original description (NVD)
Heap-based buffer overflow in Microsoft Windows Media Foundation allows an unauthorized 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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