Microsoft released its final Patch Tuesday updates of 2025 on December 9, addressing 56 security vulnerabilities across Windows, Office, Exchange Server, and other components.
This batch includes three zero-day flaws: two publicly disclosed remote code execution issues and one actively exploited elevation of privilege vulnerability.
The updates tackle two critical remote code execution vulnerabilities in Microsoft Office, both rated critical due to their potential for arbitrary code execution via malicious documents.
Dozens of important-rated issues dominate, primarily elevation of privilege flaws in Windows kernel drivers like Cloud Files Mini Filter Driver and Win32k, alongside remote code execution bugs in RRAS and ReFS. Exploitation likelihood varies, with several marked as “More Likely” or “Detected,” urging immediate patching amid holiday slowdowns.
| Vulnerability Type | Count |
|---|---|
| Remote Code Execution | 19 |
| Denial of Service | 3 |
| Elevation of Privilege | 28 |
| Information Disclosure | 4 |
| Spoofing | 2 |
| Total | 56 |
No moderate or low-severity flaws appear highlighted, but the focus remains on preventing local privilege escalation and remote attacks. Affected products span Windows 10/11/Server, Office apps (Excel, Word, Outlook, Access), Hyper-V, Azure Monitor Agent, PowerShell, and third-party like GitHub Copilot for JetBrains.
Zero-Day Vulnerabilities
Three zero-days stand out. CVE-2025-64671 in GitHub Copilot for JetBrains enables command injection for local RCE, publicly known, but exploitation is less likely. CVE-2025-54100 affects PowerShell similarly via command injection.
CVE-2025-62221, a use-after-free in Windows Cloud Files Mini Filter Driver, shows detected exploitation, marking it actively used in attacks.
| CVE ID | Component | Vulnerability Type | Severity | Exploitation Likelihood | Link |
|---|---|---|---|---|---|
| CVE-2025-62554 | Microsoft Office | Type Confusion RCE | Critical | Less Likely | Details |
| CVE-2025-62557 | Microsoft Office | Use-after-Free RCE | Critical | Less Likely | Details |
| CVE-2025-62221 | Windows Cloud Files | Use-after-Free EoP | Important | Detected | Details |
| CVE-2025-64671 | GitHub Copilot | Command Injection RCE | Important | Less Likely | Details |
| CVE-2025-54100 | PowerShell | Command Injection RCE | Important | Less Likely | Details |
| CVE-2025-62454 | Windows Cloud Files | Heap Buffer Overflow EoP | Important | More Likely | Details |
| CVE-2025-62456 | Windows ReFS | Heap Buffer Overflow RCE | Important | Unlikely | Details |
| CVE-2025-62549 | Windows RRAS | Untrusted Pointer RCE | Important | Less Likely | Details |
Organizations should prioritize testing and deploying these updates via Windows Update or the Microsoft Update Catalog, especially for zero-days and “More Likely” exploits. Extended Security Updates remain critical for Windows 10 users post-EOL.
Monitor CISA’s Known Exploited Vulnerabilities catalog for additions, and segment networks to limit lateral movement from EoP flaws. With year-end holidays approaching, automate patching to mitigate risks from the 1,100+ CVEs patched in 2025.
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