Bear in mind that, at one time, iOS devices could be jailbroken [to run arbitrary code] by simply opening a specifically-created PDF; https://www.wired.com/2011

Bear in mind that, at one time, iOS devices could be jailbroken [to run arbitrary code] by simply opening a specifically-created PDF; https://www.wired.com/2011/07/jailbreakme-3-0-unlock-your-ipad-2-from-the-browser/ https://www.wired.com/2011/07/jailbreakme-3-0-unlock-your-ip...