Microsoft Patch Tuesday December 2025 Addresses Actively Exploited Zero-Days
Microsoft released its December 2025 Patch Tuesday updates, addressing 57 security vulnerabilities across Windows 10, Windows 11, Windows Server, Office, and related services. Among these, three zero-day vulnerabilities were highlighted: CVE-2025-62221, an actively exploited privilege escalation flaw in the Windows Cloud Files Mini Filter Driver; CVE-2025-64671, a remote code execution vulnerability in GitHub Copilot for JetBrains; and CVE-2025-54100, a remote code execution issue in Windows PowerShell. The update also introduced a new warning in PowerShell to alert users when the Invoke-WebRequest command fetches web pages without safe parameters, aiming to prevent script-based attacks that exploit unsafe web content retrieval.
Throughout 2025, Microsoft addressed a total of 1,130 CVEs via Patch Tuesday releases, with 41 zero-day vulnerabilities patched, including 24 that were exploited in the wild. Elevation of Privilege and Remote Code Execution vulnerabilities made up the majority of the year's patches, reflecting ongoing attacker focus on these vectors. The December update continues Microsoft's trend of prioritizing critical and important vulnerabilities, reinforcing the need for organizations to promptly apply security updates to mitigate active threats.
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How this story unfolded
6 events from the most recent confirmed update back to the earliest known activity.
PowerShell adds warning for web-fetched scripts to counter ClickFix-style abuse
Microsoft introduced a new warning in PowerShell's Invoke-WebRequest command to reduce the risk of users accidentally executing malicious scripts fetched from the web, including techniques associated with ClickFix campaigns.
Microsoft patches three actively exploited zero-days in December
The December 2025 update fixed three zero-days under active exploitation: CVE-2025-62221, a privilege escalation flaw; CVE-2025-64671, a remote code execution bug in GitHub Copilot for JetBrains; and CVE-2025-54100, a remote code execution flaw in Windows PowerShell.
Microsoft releases December 2025 Patch Tuesday updates
On December 2025 Patch Tuesday, Microsoft released fixes for 57 vulnerabilities affecting Windows 10, Windows 11, Windows Server, Office, and related services.
Threat actors exploit major Microsoft zero-days during 2025
Notable 2025 exploitation included CVE-2025-24983 and CVE-2025-29824 in ransomware campaigns, CVE-2025-33053 used by Stealth Falcon to deploy malware, and coordinated SharePoint exploitation by Linen Typhoon, Violet Typhoon, and Storm-2603.
Microsoft fixes 41 zero-days during 2025, including 24 under active exploitation
Over the course of 2025, Microsoft patched 41 zero-day vulnerabilities, 24 of which were reported as actively exploited in the wild. Elevation of Privilege flaws were the most frequently exploited zero-days.
Microsoft patches 1,130 CVEs across 2025 Patch Tuesday releases
Throughout 2025, Microsoft addressed 1,130 vulnerabilities in its monthly Patch Tuesday updates, marking a 12% increase from 2024 and the second straight year with more than 1,000 CVEs patched.
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Microsoft December Patch Tuesday Addresses Multiple Actively Exploited Vulnerabilities
Microsoft released its December Patch Tuesday updates, addressing a total of 57 CVEs, including several critical vulnerabilities that have been actively exploited. Among the most notable is CVE-2025-62221, a Windows Cloud Files Mini Filter Driver flaw rated 7.8 on the CVSS scale, which allows local privilege escalation if an attacker already has code execution on the system. Microsoft confirmed this vulnerability is being exploited as a zero-day, underscoring the urgency for organizations to apply the patch. Additional high-severity vulnerabilities include a PowerShell Remote Code Execution flaw (CVE-2025-54100) and a GitHub Copilot for Jetbrains bug (CVE-2025-64671), both of which are publicly known but not yet observed in active exploitation. Separately, Microsoft also issued a fix for CVE-2025-9491, a high-severity vulnerability in Windows LNK files that has been actively exploited by both state-sponsored and cybercriminal groups. This flaw enables attackers to embed malicious commands in shortcut files, facilitating malware deployment and persistent access to compromised systems. Security experts emphasize the importance of prioritizing these patches, as the vulnerabilities are being leveraged in real-world attacks and could lead to significant compromise if left unaddressed.
Mar 21, 2026
Microsoft December 2025 Patch Tuesday Addresses Zero-Days and 57 Vulnerabilities
Microsoft released its December 2025 Patch Tuesday updates, addressing 57 security vulnerabilities across its product suite, including three zero-day flaws. Among the most critical issues patched is CVE-2025-62221, an actively exploited elevation of privilege vulnerability in the Windows Cloud Files Mini Filter Driver, which could allow attackers to gain SYSTEM privileges. The updates also include a fix for a remote code execution zero-day in PowerShell (CVE-2025-54100), which now prompts users with a security warning when using the `Invoke-WebRequest` command, and other critical vulnerabilities affecting Windows 10 and 11, as well as related server products. The updates are mandatory for supported systems, including those enrolled in the Extended Security Update (ESU) program, and require a system restart upon installation. CISA has added CVE-2025-62221 to its Known Exploited Vulnerabilities Catalog, urging all organizations to prioritize remediation due to evidence of active exploitation. Security advisories and technical analyses from multiple sources highlight the importance of promptly applying these patches, as the vulnerabilities present significant risks for privilege escalation and remote code execution. The December update also marks the continued support for Windows 10 through ESU, with no new features introduced, focusing solely on security and bug fixes. Organizations are advised to review the full list of addressed CVEs and ensure all relevant systems are updated to mitigate potential threats.
Mar 21, 2026
Microsoft October 2025 Patch Tuesday Addresses Multiple Zero-Days and Over 170 Vulnerabilities
Microsoft released its October 2025 Patch Tuesday security updates, addressing a total of 172 vulnerabilities across its product suite, including six zero-day vulnerabilities. The update marks a significant milestone as it is the final free security update for Windows 10, which has now reached its end of support, requiring users and enterprises to enroll in Extended Security Updates (ESU) for continued protection. Among the vulnerabilities patched, eight were rated as 'Critical,' with five being remote code execution flaws and three classified as elevation of privilege vulnerabilities. The breakdown of vulnerabilities includes 80 elevation of privilege, 11 security feature bypass, 31 remote code execution, 28 information disclosure, 11 denial of service, and 10 spoofing vulnerabilities. Notably, two of the zero-day vulnerabilities were publicly disclosed prior to the patch, affecting Windows SMB Server and Microsoft SQL Server, while three zero-days were actively exploited in the wild. One of the exploited zero-days, CVE-2025-24990, involved the Agere Modem driver, which was being abused to gain administrative privileges, prompting Microsoft to remove the vulnerable driver from supported Windows operating systems. The Patch Tuesday release also included updates for a wide range of Microsoft products and components, such as .NET, Visual Studio, Active Directory Federation Services, Microsoft Office suite, Azure services, Windows authentication methods, and various Windows system components. The update was described as the largest Patch Tuesday release to date, with 167 CVEs directly patched according to some sources, excluding additional vulnerabilities in Chromium, MITRE, GitHub, CERT/CC, and cloud services that were addressed separately. The security updates did not include fixes for vulnerabilities in Microsoft Edge, Azure, or Mariner that were released earlier in the month. Microsoft emphasized the importance of these updates, especially for organizations still running Windows 10, as the cessation of free support increases the risk of exposure to unpatched vulnerabilities. The comprehensive nature of the update reflects the ongoing complexity and breadth of the Microsoft ecosystem, with critical patches spanning from core Windows components to cloud and developer tools. Security professionals are advised to prioritize the deployment of these patches, particularly those addressing actively exploited zero-days and critical remote code execution vulnerabilities. The update also highlights the evolving threat landscape, with attackers increasingly targeting third-party drivers and core system components to escalate privileges. Organizations are encouraged to review the full list of patched vulnerabilities and assess their exposure, especially in light of the end of support for Windows 10. The October 2025 Patch Tuesday underscores the necessity of timely patch management and the challenges posed by legacy systems in maintaining a secure enterprise environment.
Mar 21, 2026