Actionscript 3 - Multiple navigateToURL() trigger multiple authorization popups

Question

I have to execute multiple navigateToURL in an swf on file:// protocol (so I can't use ExternalInterface). Unfortunately, I can't set this swf as trusted. I am using this code:

var urls:Array = [
'file:///tmp/1',
'file:///tmp/2',
'file:///tmp/3'
];

var timer:Timer = new Timer(300, urls.length);
timer.addEventListener(TimerEvent.TIMER, onTimer);
function onTimer(e:TimerEvent):void {
    navigateToURL(new URLRequest(urls[timer.currentCount - 1]), '_blank');
}
timer.start();

Unfortunately, now flash when navigateToURL() is used in an untrusted swf, ask for permissions in a popup like this

https://i.stack.imgur.com/pWQuB.jpg

with this code, this popup appears every time navigateToURL is executed, in my case 3 times, and it makes the program unusable. I thought flash was designed to ask for permissions just once.

There's a solution to avoid this behaviour?