Breeze Cache <= 2.4.4 - Unauthenticated Arbitrary File Upload via fetch_gravatar_from_remote

Description

The Breeze Cache plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the 'fetch_gravatar_from_remote' function in all versions up to, and including, 2.4.4. This makes it possible for unauthenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible. The vulnerability can only be exploited if "Host Files Locally - Gravatars" is enabled, which is disabled by default.