vBulletin 'admincalendar.php' SQL Injection Vulnerability

Summary
vBulletin is prone to an SQL-injection vulnerability because it fails to sufficiently sanitize user-supplied data before using it in an SQL query. Exploiting this issue could allow an attacker to compromise the application, access or modify data, or exploit latent vulnerabilities in the underlying database. Note that to succeed, the attacker must have an administrative account with 'calendar' administrator access. vBulletin 3.7.3.pl1 is vulnerable other versions may also be affected.
Solution
Upgrade to newest Version of VBulletin.