The WP-Polls plugin for WordPress is vulnerable to SQL Injection via COOKIE in all versions up to, and including, 2.77.2 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query.  This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries. Those queries are stored and results are not displayed to the attacker, which means they cannot be exploited to obtain any additional information about the database. However, a properly configured payload allows for the injection of malicious JavaScript resulting in Stored Cross-Site Scripting.