Your simple text editor just became a high-risk entry point. 📝
CVE-2026-20841 · Severity 7.8 · Remote code execution via Markdown links in Windows 11 Notepad.
We are seeing attackers distribute crafted Markdown files that trigger unverified protocol launches. One click on a “README” file is enough to initiate a malicious file download on @[Microsoft](urn:li:organization:1035) systems.
The latest Patch Tuesday update addresses this, but only for the Store-updated version of the app. This vulnerability illustrates how even basic native apps are now being weaponized.
The uncomfortable truth: If you don’t restrict protocol handlers, any app that can render a link becomes a potential execution vector.
→ Update the Notepad App via the Microsoft Store to version 11.2510 or higher.
→ Block high-risk protocol handlers like ms-appinstaller at the operating system level.
→ Audit your environment for unexpected parent-child process chains involving Notepad.exe.
Do you currently restrict which protocol handlers are allowed to launch on corporate endpoints? 👇
#CloudSecurity #DataPrivacy #SecurityOperations #CyberRisk #vCISO #CodeDefence