An issue was discovered in phpMyAdmin 4.8.x before 4.8.2, in which an attacker can include (view and potentially execute) files on the server. The vulnerability comes from a portion of code where pages are redirected and loaded within phpMyAdmin, and an improper test for whitelisted pages. An attacker must be authenticated, except in the "$cfg['AllowArbitraryServer'] = true" case (where an attacker can specify any host he/she is already in control of, and execute arbitrary code on phpMyAdmin) and the "$cfg['ServerDefault'] = 0" case (which bypasses the login requirement and runs the vulnerable code without any authentication).
https://www.phpmyadmin.net/security/PMASA-2018-4/
https://www.exploit-db.com/exploits/45020/
https://www.exploit-db.com/exploits/44928/
https://www.exploit-db.com/exploits/44924/
https://security.gentoo.org/glsa/201904-16
http://www.securityfocus.com/bid/104532
http://packetstormsecurity.com/files/164623/phpMyAdmin-4.8.1-Remote-Code-Execution.html