Microsoft has released a patch for a significant vulnerability in Notepad on Windows 11 that could allow attackers to execute code by opening a Markdown file and clicking on a malicious link. This vulnerability was due to how Notepad processed links within Markdown files, which could trigger unverified protocols to load remote content. The patch now includes a security warning before such links can be activated. Users are advised to check for updates via Windows Update and the Microsoft Store to ensure Notepad and related components are up to date. Security tips include inspecting URLs before clicking and keeping Microsoft Defender features enabled.