Windows 10: Heap-based buffer overflow in Bind Filter Driver allows privilege escalation
Summary
A heap-based buffer overflow in the Windows Bind Filter Driver (bindflt.sys) on Windows 10 Version 21H2 allows an authorized local attacker to elevate privileges. The attacker needs a valid low-privilege local account and no user interaction is required. Successful exploitation could give high impact to confidentiality, integrity and availability.
Affected
- Windows 10 Version 21H2: builds 10.0.19044.0 to below 10.0.19044.7807
Fixed in
- Windows 10 Version 21H2: build 10.0.19044.7807 or later (per the CNA record; to be confirmed on the MSRC Security Update Guide before rollout)
Workaround
Unknown.
Exploitation
- No public exploitation confirmed.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- Not listed in CISA KEV according to OpenCVE.
Our recommendation
- Deploy the October 2026 cumulative update for Windows 10 21H2 after confirming the fixed build on the MSRC advisory.
- Identify remaining Windows 10 21H2 devices and plan an upgrade if they are no longer supported.
- Keep standard-user and least-privilege controls in place, since an attacker needs a local foothold.
- Monitor the MSRC advisory and KEV status for changes.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Windows Bind Filter Driver
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5126655, KB5126657, KB5126646, KB5127648, KB5126653, KB5127646
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-83692 msrc.microsoft.com
- OpenCVE: CVE-2026-83692 app.opencve.io
- Vulners CVE List: CVE-2026-83692 vulners.com
- Vulners Microsoft CVE: MS:CVE-2026-83692 vulners.com
- Batcmd: bindflt service on Windows 10 batcmd.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, 03:22.
Original description (NVD)
Heap-based buffer overflow in Windows Bind Filter Driver 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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