The Link Library plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Link Additional Parameters in all versions up to, and including, 7.7.3 due to insufficient input sanitization and output escaping. 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.

The Link Library WordPress plugin before 7.9.6 does not sanitize a user-supplied destination folder before writing a generated image to disk, allowing users with the Contributor role and above to create directories and write or overwrite image files anywhere the web server can write, including outside the site's document root.

The written file name is always numeric with a fixed image extension, so executable code cannot be planted this way.