PHP 'is_a()' Function Remote File Include Vulnerability

Summary
PHP is prone to a remote file-include vulnerability because it fails to properly implement the 'is_a()' function. Exploiting this issue may allow an attacker to compromise PHP applications using the affected function. This may also result in a compromise of the underlying system other attacks are also possible. PHP 5.3.7 and 5.3.8 are vulnerable.
Solution
Updates are available. Please see the references for more information.
References