Input validation vulnerability in WP Post Statistics (Visitors & Visits Counter) 2.5

The WP Post Statistics (Visitors & Visits Counter) plugin for WordPress is vulnerable to a type of attack called Stored Cross-Site Scripting. This attack is possible for versions up to and including 2.5 because the plugin does not protect itself against malicious inputs and does not properly encode data it outputs. Unauthenticated attackers can take advantage of this vulnerability by injecting malicious web scripts into pages. When a user visits an injected page, the malicious web script will execute.