Patch Tuesday December 2025: what's exploited and what to install first
Microsoft released fixes for 57 vulnerabilities on Dec 9, 2025. 1 is already being exploited by attackers, so install that fix first. 2 were publicly disclosed before the fix came out. 2 are rated Critical.
Install these first: already exploited
- Windows Cloud Files Mini Filter DriverExploitedImportantCVSS 7.8Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability
What to do: Install this month's Microsoft updates and restart. Attackers are already using this flaw.
Publicly disclosed before the fix
Details were public before Microsoft's update, so attacks often follow quickly.
- CVSS 8.4 GitHub Copilot for Jetbrains Remote Code Execution Vulnerability
- CVSS 7.8 PowerShell Remote Code Execution Vulnerability
Critical fixes
- CVSS 8.4 Microsoft Office Remote Code Execution Vulnerability
- CVSS 8.4 Microsoft Office Remote Code Execution Vulnerability
How to install this month's updates
- Windows PCs: Settings → Windows Update → Check for updates, install, and restart. Restarting is what actually applies the fix.
- Managed fleets: approve this month's updates in Intune, Windows Update for Business or WSUS, and push the exploited fixes first instead of waiting for your normal ring schedule.
- Microsoft 365 Apps / Office: usually updates itself; in any Office app, File → Account → Update Options → Update Now to make sure.
- Servers: Exchange, SharePoint and SQL Server need their own update packages; they don't come through Windows Update alone.
- Check it worked: confirm the build number afterwards (run
winver) or check with our version checker.
By type
| Type | Fixes |
|---|---|
| Elevation of Privilege | 29 |
| Remote Code Execution | 19 |
| Information Disclosure | 4 |
| Denial of Service | 3 |
| Spoofing | 2 |
Most-patched products
| Product | Fixes |
|---|---|
| Microsoft Office Excel | 6 |
| Windows Projected File System | 4 |
| Windows Cloud Files Mini Filter Driver | 3 |
| Windows Routing and Remote Access Service (RRAS) | 3 |
| Windows DirectX | 3 |
| Windows Shell | 3 |
| Microsoft Office Word | 3 |
| Microsoft Brokering File System | 2 |
The next Patch Tuesday is Nov 10, 2026 (in 5 days). Microsoft usually publishes around 10 a.m. Pacific; this page updates within the hour.
Questions
What should I patch first from Patch Tuesday December 2025?
The 1 exploited flaw: Windows Cloud Files Mini Filter Driver Elevation of Privilege Vulnerability. Attackers are already using it.
When is the next Patch Tuesday?
Nov 10, 2026. Microsoft releases security updates on the second Tuesday of every month.
Source: Microsoft's December 2025 release notes and CISA's exploited-vulnerability catalog. Counts exclude Chromium fixes shipped in Microsoft Edge. Microsoft last revised this release on Nov 5, 2026. General information only; confirm details with Microsoft.