Input validation vulnerability in Recent Posts Slider 1.1

The Recent Posts Slider plugin for WordPress is vulnerable to a type of attack called Reflected Cross-Site Scripting. This type of attack allows unauthenticated attackers to insert malicious code into pages on a website. Whenever a user views the page, the malicious code will execute. This vulnerability affects all versions of the plugin up to and including version 1.1 because there was not enough input sanitization and output escaping.