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Microsoft Addresses Critical Zero-Day and 56 Flaws in December 2025 Patch Tuesday
Microsoft has released a critical security update addressing at least 56 vulnerabilities across its Windows operating systems and related software. this final “Patch Tuesday” of 2025 tackles a currently exploited zero-day bug, alongside two other publicly known vulnerabilities, underscoring the ongoing battle against cyber threats.
Despite a relatively quiet few months in terms of update volume, Microsoft successfully patched a ample 1,129 vulnerabilities throughout 2025 – an 11.9% increase compared to the 1,005 vulnerabilities addressed in 2024. according to one analyst at Tenable, this marks the second consecutive year Microsoft has exceeded one thousand patched vulnerabilities, and only the third time in the company’s history.
The most pressing issue addressed in today’s update is a zero-day vulnerability, designated CVE-2025-62221. This flaw is a privilege escalation vulnerability impacting Windows 10 and later versions, residing within the “Windows Cloud Files Mini Filter Driver.” This system driver is crucial for enabling cloud applications to interact with the file system. “This is especially concerning,” a lead software engineer at Rapid7 noted, “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.”
Only three vulnerabilities received Microsoft’s highest “critical” severity rating. Two,CVE-2025-62554 and CVE-2025-62557,relate to Microsoft Office and can be exploited simply by viewing a malicious email in the Preview Pane. The third, CVE-2025-62562, affects microsoft Outlook, though Microsoft states the preview Pane is not a vector for this specific vulnerability.
Though, microsoft has identified a set of non-critical privilege escalation bugs as the most likely to be exploited in the near term. These include:
- 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
A senior director of threat research at Immersive emphasized the prevalence of privilege escalation flaws in successful host compromises. “We don’t know why Microsoft has marked these specifically as more likely,” they stated, “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.”
Beyond these, a particularly noteworthy vulnerability is CVE-2025-64671, a remote code execution flaw within the Github Copilot Plugin for Jetbrains, an AI-powered coding assistant used by both Microsoft and GitHub. This flaw could allow attackers to execute arbitrary code by manipulating the large language model (LLM) to bypass security measures and inject malicious instructions into a user’s “auto-approve” settings.
CVE-2025-64671 is symptomatic of a larger security trend impacting the AI coding space.A security researcher has coined the term “IDEsaster” to describe a systemic crisis encompassing over 30 vulnerabilities across nearly a dozen leading AI coding platforms, including Cursor, Windsurf, Gemini CLI, and Claude code.
the update also addresses CVE-2025-54100, a remote code execution vulnerability in Windows Powershell on Windows Server 2008 and later, allowing unauthenticated attackers to execute code with user-level privileges.
For a more detailed breakdown of today’s security updates, users are encouraged to consult the roundup provided by the SANS Internet Storm Center. As always, Microsoft encourages users to report any issues encountered during the patch request process.
