Windows CCFFilter Driver: Use-after-free leads to remote code execution
Summary
A use-after-free flaw (CWE-416) in the Windows CCFFilter Driver may allow an attacker to execute code. The CNA scores it CVSS 9.8 as unauthenticated and network-reachable, which would make it critical. ZDI's October 2026 review instead describes it as requiring an authorized local attacker, so the actual exposure is disputed and must be verified against the MSRC advisory. The function of this driver and its default reachability are unknown.
Affected
- Windows 10 Version 1607 (10.0.14393.0 to below 10.0.14393.9612)
- Windows 10 Version 1809 (10.0.17763.0 to below 10.0.17763.9376)
- Windows Server 2016, including Server Core (10.0.14393.0 to below 10.0.14393.9612)
- Windows Server 2019, including Server Core (10.0.17763.0 to below 10.0.17763.9376)
- Windows Server 2022 (10.0.20348.0 to below 10.0.20348.5761)
- Windows Server 2025, including Server Core (10.0.26100.0 to below 10.0.26100.33650)
- Some secondary sources also list Windows 10 21H2, 22H2 and Windows 11 23H2; this is unverified.
Fixed in
- Windows 10 1607 and Server 2016: 10.0.14393.9612 (per aggregator data, verify on MSRC)
- Windows 10 1809 and Server 2019: 10.0.17763.9376 (per aggregator data, verify on MSRC)
- Windows Server 2022: 10.0.20348.5761 (per aggregator data, verify on MSRC)
- Windows Server 2025: 10.0.26100.33650 (per aggregator data, verify on MSRC)
- Patches are expected in the October 2026 Patch Tuesday updates; KB numbers are unverified.
Workaround
Unknown.
Exploitation
- Not listed in CISA KEV.
- CISA SSVC: exploitation none, automatable yes, technical impact total.
- EPSS is roughly 0.01.
- No public proof-of-concept or exploit was found in our searches; this does not prove none exists.
Our recommendation
- Read the MSRC advisory and FAQ to confirm affected builds and whether network exposure is required.
- Patch affected Windows 10 and Windows Server systems in the next maintenance window; patching is the only confirmed fix.
- Prioritise servers reachable from untrusted networks.
- Monitor CISA KEV and public exploit releases, and re-check NVD for changes to the analysis status or CWE.
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-2026-83780 msrc.microsoft.com
- OpenCVE: CVE-2026-83780 app.opencve.io
- ZDI: October 2026 security update review www.zerodayinitiative.com
- Vulners NVD record: CVE-2026-83780 vulners.com
- Vulners MSCVE record: CVE-2026-83780 vulners.com
- Strix: CVE-2026-83780 www.strix.ai
- Vulners Rapid7 Microsoft Windows CVE-2026-83780 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 30 Oct 2026, 18:35.
Original description (NVD)
Use after free in Windows CCFFilter Driver 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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