WP-Syntax plugin 0.9.1 and earlier for Wordpress, with register_globals enabled, allows remote attackers to execute arbitrary PHP code via the test_filter[wp_head] array parameter to test/index.php, which is used in a call to the call_user_func_array function.
Improper Input Validation The product receives input or data, but it does
not validate or incorrectly validates that the input has the
properties that are required to process the data safely and
correctly.