Microsoft’s December 2025 Patch Tuesday: Addressing 56 Vulnerabilities, Including Active Exploits and Zero-Days
In its final Patch Tuesday release of 2025, Microsoft has rolled out security updates addressing 56 vulnerabilities across its product suite. This comprehensive update includes fixes for three critical flaws and 53 important ones, underscoring the company’s commitment to fortifying its software against potential threats.
Breakdown of Vulnerabilities:
– Critical Vulnerabilities: Three vulnerabilities have been classified as critical, primarily due to their potential to allow remote code execution (RCE). Notably:
– CVE-2025-62554 and CVE-2025-62557: Both are RCE vulnerabilities within Microsoft Office, each carrying a CVSS score of 8.4. Exploitation could occur if a user opens a malicious document, enabling attackers to execute arbitrary code.
– CVE-2025-62562: An RCE vulnerability in Microsoft Outlook, also with a CVSS score of 7.8, which could be exploited through specially crafted emails.
– Important Vulnerabilities: The remaining 53 vulnerabilities span various categories:
– Elevation of Privilege: 29 vulnerabilities that could allow attackers to gain higher-level permissions on a system.
– Remote Code Execution: 18 vulnerabilities enabling attackers to execute code remotely.
– Information Disclosure: Four vulnerabilities that could lead to unauthorized information exposure.
– Denial of Service: Three vulnerabilities that could disrupt service availability.
– Spoofing: Two vulnerabilities that could allow attackers to impersonate other entities.
Zero-Day Vulnerabilities:
Among the addressed vulnerabilities, three were zero-day flaws, indicating they were either publicly disclosed or actively exploited before patches were available:
1. CVE-2025-62221: An elevation of privilege vulnerability in the Windows Cloud Files Mini Filter Driver, with a CVSS score of 7.8. Exploitation could grant attackers SYSTEM privileges. This flaw has been actively exploited in the wild, prompting immediate attention.
2. CVE-2025-54100: A command injection vulnerability in Windows PowerShell, allowing unauthorized local code execution.
3. CVE-2025-64671: A command injection vulnerability in GitHub Copilot for JetBrains, also permitting unauthorized local code execution.
Implications and Recommendations:
The active exploitation of CVE-2025-62221 is particularly concerning. This vulnerability allows attackers to escalate privileges, potentially leading to full system compromise. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added this flaw to its Known Exploited Vulnerabilities catalog, urging organizations to apply the patch by December 30, 2025.
Organizations are advised to prioritize the deployment of these patches, especially for systems running Microsoft Office, Outlook, and Windows components susceptible to the aforementioned vulnerabilities. Given the critical nature of some flaws and the active exploitation of others, timely updates are essential to maintain system integrity and security.
Conclusion:
Microsoft’s December 2025 Patch Tuesday serves as a crucial reminder of the ever-evolving cybersecurity landscape. By addressing these 56 vulnerabilities, including actively exploited zero-days, Microsoft aims to enhance the security posture of its users. Organizations and individuals alike should remain vigilant, ensuring that their systems are updated promptly to mitigate potential risks.
