This indicates an attack attempt against a remote Code Execution vulnerability in phpMyAdmin.
The vulnerability is caused by insufficient sanitizing in the "find" parameter passed to "tbl_find_replace.php". A remote attacker may be able to exploit this to execute arbitrary code within the context of the application, via a crafted HTTP request.
phpMyAdmin 4.0.x before 188.8.131.52
phpMyAdmin 4.4.x before 184.108.40.206
phpMyAdmin 4.6.x before 4.6.3
System Compromise: Remote attackers can gain control of vulnerable systems.
Refer to the vendor's website for updates.