Microsoft will block 120 high-risk file extensions in OneNote>
nSane Forums – Alf9872000
As a consequence of ongoing phishing campaigns using Microsoft OneNote, Microsoft announced that it would harden the application against phishing attacks in early March 2023. Microsoft planned to start the rollout of the security change in April 2023. The company has now published several support documents that provide system administrators and users with additional information.

The main change that Microsoft will introduce changes how 120 high-risk file extensions are handled by the application. OneNote showed a warning to users when they were about to open a high-risk attachment. Users were able to bypass the warning to open the extension.

OneNote users see “Your administrator has blocked your ability to open this file type in OneNote”. The dialog has just an ok button, and a close window control, but no option anymore to execute the embedded file.
Link: https://nsaneforums.com/news/security-privacy-news/microsoft-will-block-120-high-risk-file-extensions-in-onenote-r14126/