The Fuse Social Floating Sidebar plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the file upload functionality in all versions up to, and including, 5.4.10 due to insufficient validation of SVG files. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
https://wordpress.org/plugins/fuse-social-floating-sidebar/#developers