Input validation vulnerability in Secondary Title 2.0.9.1

The Secondary Title plugin for WordPress is vulnerable to a type of malicious code called Stored Cross-Site Scripting. This vulnerability affects versions up to and including 2.0.9.1, and is caused by a lack of security measures to check the input data and to prevent malicious code from being executed. This means that if an attacker with contributor-level access or higher has the ability to inject malicious code into pages, that code will be executed whenever someone views the page.