EWWW Image Optimizer < 8.8.0 - Admin+ WebP File Rename and Deletion via Unrestricted Path in WebP Migration Handler

Description

The plugin does not confine a WebP-derivative file migration routine to the current site's own uploads directory, letting an attacker with Administrator-level access rename or delete existing WebP-derivative image files outside that scope, including, on a multisite network, files belonging to a different site they have no access to.