ASA-2019-00588 – vBulletin: Remote Code Execution in updateAvatar endpoint

User input passed through the "data[extension]" and "data[filedata]" parameters to the "ajax/api/user/updateAvatar" endpoint is not properly validated before being used to update users' avatars. This can be exploited to inject and execute arbitrary PHP code. Successful exploitation of this vulnerability requires the "Save Avatars as Files" option to be enabled (disabled by default).