Input validation vulnerability in Linker 1.2.1

The WordPress Linker plugin has a security issue that affects all versions up to and including version 1.2.1. This issue allows malicious users with contributor-level or higher permissions to inject malicious web scripts onto pages. These scripts will then execute whenever someone visits the page. This happens because the plugin does not properly sanitize user-supplied data before outputting it, or protect against malicious code.