Windows Media Foundation: Heap-based buffer overflow enables code execution
Summary
A heap-based buffer overflow in the Microsoft Windows Media Foundation component allows an unauthorized attacker to execute code over the network. The attack requires that a user interacts with a manipulated file or content, as the CVSS vector indicates UI:R. The official record lists affected builds across Windows 10, Windows 11 and Windows Server 2012 to 2016, including Windows 10 Version 1607 and Windows Server 2016.
Affected
- Windows 10 Version 1607 (builds below 10.0.14393.9612)
- Windows Server 2016 (builds below 10.0.14393.9612)
- Windows 10 Version 1809 (builds below 10.0.17763.9376)
- Windows 10 Version 21H2 and 22H2 (builds below 10.0.19045.7807)
- Windows 11 Version 23H2, 24H2, 25H2 and 26H1/26H2 (see the MSRC update guide for exact builds)
- Windows Server 2012 and 2012 R2 (see the MSRC update guide for exact builds)
Fixed in
- Windows 10 Version 1607 and Windows Server 2016: build 10.0.14393.9612 or later
- Other versions: the fixed builds are listed in the MSRC update guide. Verify the build numbers there before deployment.
Workaround
Unknown. No vendor-documented workaround was found.
Exploitation
- CISA SSVC assessment: exploitation none, not automatable, total technical impact.
- No public proof-of-concept code found; CIRCL reports no technical details.
- A Tenable plugin is flagged as exploit available, but the basis is not stated.
- EPSS about 0.84 percent.
Our recommendation
- Identify all systems running Windows 10 Version 1607 or Windows Server 2016 and prioritize them for patching.
- Install the October 2026 security update from Microsoft and confirm the build number afterwards.
- Check whether vulnerable systems are reachable from the internet or only from the internal network, and restrict exposure.
- Verify the Microsoft lifecycle status of Windows 10 Version 1607; plan replacement or isolation of unsupported systems.
- Monitor for unusual activity on affected systems and educate users about opening untrusted files or links.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Remote code execution – Microsoft Windows Media Foundation
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation unlikely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126651, KB5126655, KB5126657, KB5126646, KB5127648, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70258 msrc.microsoft.com
- OpenCVE: CVE-2026-70258 app.opencve.io
- Vulners NVD mirror: CVE-2026-70258 vulners.com
- Tenable plugin 365471 www.tenable.com
- CIRCL via Vulners: CVE-2026-70258 vulners.com
- Vulners VulnRichment: CVE-2026-70258 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 31 Oct 2026, 18:50.
Original description (NVD)
Heap-based buffer overflow in Microsoft Windows Media Foundation allows an unauthorized attacker to execute code over a network.
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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