libraries/server_synchronize.lib.php in the Synchronize implementation in phpMyAdmin 3.x before 3.3.10.2 and 3.4.x before 3.4.3.1 does not properly quote regular expressions, which allows remote authenticated users to inject a PCRE e (aka PREG_REPLACE_EVAL) modifier, and consequently execute arbitrary PHP code, by leveraging the ability to modify the SESSION superglobal array.