SMTP by BestWebSoft < 1.2.0 - Authenticated (Administrator+) Arbitrary File Upload

Description

The SMTP by BestWebSoft plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the 'save_options' function in all versions up to, and including, 1.1.9. This makes it possible for authenticated attackers, with Administrator-level access and above, to upload arbitrary files on the affected site's server which may make remote code execution possible.