December Patch Tuesday Brings Critical Microsoft, Notepad++, Fortinet, and Ivanti Security Fixes

While December’s Patch Tuesday gave us a lighter release than normal, it arrived with several urgent vulnerabilities that need attention immediately. In all, Microsoft released 57 CVE patches to finish out 2025, including one flaw already under active exploitation and two others that were publicly disclosed. Notably, critical security updates also came from Notepad++, Ivanti, and Fortinet this cycle, making it particularly important for system administrators and enterprise security teams alike. 

The most critical of Microsoft’s disclosures this month is CVE-2025-62221, a Windows Cloud Files Mini Filter Driver bug rated 7.8 on the CVSS scale. It allows for privilege escalation: an attacker who has code execution rights can leverage the bug to escalate to full system-level access. Researchers say this kind of bug is exploited on a regular basis in real-world intrusions, and “patching ASAP” is critical. Microsoft hasn’t disclosed yet which threat actors are actively exploiting this flaw; however, experts explain that bugs like these “tend to pop up in almost every big compromise and are often used as stepping stones to further breach”. 

Another two disclosures from Microsoft were CVE-2025-54100 in PowerShell and CVE-2025-64671, impacting GitHub Copilot for JetBrains. Although these are not confirmed to be exploited, they were publicly disclosed ahead of patching. Graded at 8.4, the Copilot vulnerability would have allowed for remote code execution via malicious cross-prompt

[…]
Content was cut in order to protect the source.Please visit the source for the rest of the article.