An issue was discovered in the Popup Maker plugin before 1.8.13 for WordPress. An unauthenticated attacker can partially control the arguments of the do_action function to invoke certain popmake_ or pum_ methods, as demonstrated by controlling content and delivery of popmake-system-info.txt (aka the "support debug text file").
https://wpvulndb.com/vulnerabilities/9907
https://github.com/PopupMaker/Popup-Maker/blob/master/CHANGELOG.md