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Microsoft Patch Tuesday, December 2025 Edition

9 December 2025 at 18:18

Microsoft today pushed updates to fix at least 56 security flaws in its Windows operating systems and supported software. This final Patch Tuesday of 2025 tackles one zero-day bug that is already being exploited, as well as two publicly disclosed vulnerabilities.

Despite releasing a lower-than-normal number of security updates these past few months, Microsoft patched a whopping 1,129 vulnerabilities in 2025, an 11.9% increase from 2024. According to Satnam Narang at Tenable, this year marks the second consecutive year that Microsoft patched over one thousand vulnerabilities, and the third time it has done so since its inception.

The zero-day flaw patched today is CVE-2025-62221, a privilege escalation vulnerability affecting Windows 10 and later editions. The weakness resides in a component called the “Windows Cloud Files Mini Filter Driver” — a system driver that enables cloud applications to access file system functionalities.

“This is particularly concerning, as the mini filter is integral to services like OneDrive, Google Drive, and iCloud, and remains a core Windows component, even if none of those apps were installed,” said Adam Barnett, lead software engineer at Rapid7.

Only three of the flaws patched today earned Microsoft’s most-dire “critical” rating: Both CVE-2025-62554 and CVE-2025-62557 involve Microsoft Office, and both can exploited merely by viewing a booby-trapped email message in the Preview Pane. Another critical bug — CVE-2025-62562 — involves Microsoft Outlook, although Redmond says the Preview Pane is not an attack vector with this one.

But according to Microsoft, the vulnerabilities most likely to be exploited from this month’s patch batch are other (non-critical) privilege escalation bugs, including:

CVE-2025-62458 — Win32k
CVE-2025-62470 — Windows Common Log File System Driver
CVE-2025-62472 — Windows Remote Access Connection Manager
CVE-2025-59516 — Windows Storage VSP Driver
CVE-2025-59517 — Windows Storage VSP Driver

Kev Breen, senior director of threat research at Immersive, said privilege escalation flaws are observed in almost every incident involving host compromises.

“We don’t know why Microsoft has marked these specifically as more likely, but the majority of these components have historically been exploited in the wild or have enough technical detail on previous CVEs that it would be easier for threat actors to weaponize these,” Breen said. “Either way, while not actively being exploited, these should be patched sooner rather than later.”

One of the more interesting vulnerabilities patched this month is CVE-2025-64671, a remote code execution flaw in the Github Copilot Plugin for Jetbrains AI-based coding assistant that is used by Microsoft and GitHub. Breen said this flaw would allow attackers to execute arbitrary code by tricking the large language model (LLM) into running commands that bypass the user’s “auto-approve” settings.

CVE-2025-64671 is part of a broader, more systemic security crisis that security researcher Ari Marzuk has branded IDEsaster (IDE  stands for “integrated development environment”), which encompasses more than 30 separate vulnerabilities reported in nearly a dozen market-leading AI coding platforms, including Cursor, Windsurf, Gemini CLI, and Claude Code.

The other publicly-disclosed vulnerability patched today is CVE-2025-54100, a remote code execution bug in Windows Powershell on Windows Server 2008 and later that allows an unauthenticated attacker to run code in the security context of the user.

For anyone seeking a more granular breakdown of the security updates Microsoft pushed today, check out the roundup at the SANS Internet Storm Center. As always, please leave a note in the comments if you experience problems applying any of this month’s Windows patches.

December Patch Tuesday fixes three zero-days, including one that hijacks Windows devices

10 December 2025 at 11:06

These updates from Microsoft fix serious security issues, including three that attackers are already exploiting to take control of Windows systems.

In total, the security update resolves 57 Microsoft security vulnerabilities. Microsoft isn’t releasing new features for Windows 10 anymore, so Windows 10 users will only see security updates and fixes for bugs introduced by previous security updates.

What’s been fixed

Microsoft releases important security updates on the second Tuesday of every month—known as “Patch Tuesday.” This month’s patches fix critical flaws in Windows 10, Windows 11, Windows Server, Office, and related services.

There are three zero‑days: CVE‑2025‑62221 is an actively exploited privilege‑escalation bug in the Windows Cloud Files Mini Filter Driver. Two are publicly disclosed flaws: CVE-2025-64671, which is a GitHub Copilot for JetBrains remote code execution (RCE) vulnerability, and CVE‑2025‑54100, an RCE issue in Windows PowerShell.

PowerShell received some extra attention, as from now on users will be warned whenever the Invoke‑WebRequest command fetches web pages without safe parameters.​

The warning is to prevent accidental script execution from web content. It highlights the risk that script code embedded in a downloaded page might run during parsing, and recommends using the -UseBasicParsing switch to avoid running any page scripts.

There is no explicit statement from Microsoft tying the new Invoke‑WebRequest warning directly to ClickFix, but it clearly addresses the abuse pattern that ClickFix and similar campaigns rely on: tricking users into running web‑fetched PowerShell code without understanding what it does.

How to apply fixes and check you’re protected

These updates fix security problems and keep your Windows PC protected. Here’s how to make sure you’re up to date:

1. Open Settings

  • Click the Start button (the Windows logo at the bottom left of your screen).
  • Click on Settings (it looks like a little gear).

2. Go to Windows Update

  • In the Settings window, select Windows Update (usually at the bottom of the menu on the left).

3. Check for updates

  • Click the button that says Check for updates.
  • Windows will search for the latest Patch Tuesday updates.
  • If you have selected automatic updates earlier, you may see this under Update history:
Successfully installed security updates
  • Or you may see a Restart required message, which means all you have to do is restart your system and you’re done updating.
  • If not, continue with the steps below.

4. Download and Install

  • If updates are found, they’ll start downloading right away. Once complete, you’ll see a button that says Install or Restart now.
  • Click Install if needed and follow any prompts. Your computer will usually need a restart to finish the update. If it does, click Restart now.

5. Double-check you’re up to date

  • After restarting, go back to Windows Update and check again. If it says You’re up to date, you’re all set!
You're up to date

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