CVE-2026-84009
Windows Projected File System Tampering Vulnerability
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an authorized attacker to perform tampering locally.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Windows Projected File System Tampering Vulnerability
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an authorized attacker to perform tampering locally.
- Record
CVE-2026-84009- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C - Weakness
- CWE-367
- Updated
- 2026-11-10
EUVDEUVD-2026-99446
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an authorized attacker to perform tampering locally.
- Record
EUVD-2026-99446- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C - Updated
- 2026-11-10
GitHub AdvisoriesGHSA-3hrm-g38h-q887
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an...
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an authorized attacker to perform tampering locally.
- Record
GHSA-3hrm-g38h-q887- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-367
- Updated
- 2026-11-02
NVD
Time-of-check time-of-use (toctou) race condition in Windows Projected File System allows an authorized attacker to perform tampering locally.
- Record
CVE-2026-84009- CVSS 3.1
- 4.7 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N - Weakness
- CWE-367
- Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 1809
- microsoft windows 10 version 21h2
- microsoft windows 10 version 22h2
- microsoft windows 11 version 23h2
- microsoft windows 11 version 24h2
- microsoft windows 11 version 25h2
- microsoft windows 11 version 26h1
- microsoft windows 11 version 26h2
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server 2022
- microsoft windows server 2025
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | EUVD | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-84009 is a medium vulnerability (CVSS 4.7) in Microsoft Windows 10 Version 1809, published October 13, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.20%, the 9th percentile. No source names a fixed version.