CVE-2025-21361

FAQ

How could an attacker exploit this vulnerability?

The attacker would be able to bypass the protection in Outlook that prevents a potentially dangerous file extension from being attached enabling a remote code execution.

Which version of Outlook for Mac does this affect?

This vulnerability only affects the Legacy version of Outlook for Mac which is described in this documentation: Outlook for Mac. Customers who have enabled the new Outlook experience are not affected.

According to the CVSS metric, the attack vector is local (AV:L). Why does the CVE title indicate that this is a remote code execution?

The word Remote in the title refers to the location of the attacker. This type of exploit is sometimes referred to as Arbitrary Code Execution (ACE). The attack itself is carried out locally.

For example, when the score indicates that the Attack Vector is Local and User Interaction is Required, this could describe an exploit in which an attacker, through social engineering, convinces a victim to download and open a specially crafted file from a website which leads to a local attack on their computer.

Is the Attachment Preview Pane an attack vector for this vulnerability?

Yes. The attachment Preview Pane that is accessed when a user clicks to preview an attached file is an attack vector; however, the email Preview Pane itself is not.