The Product Addons and Product Options With Custom Fields WordPress plugin before 1.6.15 does not restrict an unauthenticated file-upload endpoint and accepts SVG files that are stored and served inline, allowing an unauthenticated attacker to upload a malicious SVG whose embedded script executes in the session of any user (such as an administrator) who later opens the file.
https://wpscan.com/vulnerability/8ae2ff84-a4a0-4fb1-842b-b3193e673d27/