CVE-2019-25147

The Pretty Links plugin for WordPress is vulnerable to Stored Cross-Site Scripting via various IP headers as well as the referer header in versions up to, and including, 2.1.9 due to insufficient input sanitization and output escaping in the track_link function. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Source: CVE-2019-25147