New Javascript Error on a Page with Flash .swf File in Firefox Only

I recently have started using the onerror Javascript function to see what kind of errors our visitors are experiencing. I have this onerror function making an AJAX call to send me an email when an error occurs. I'm noticing that many of our Firefox visitors are getting an error on a page with a .swf file. After Googling this, it appears to be related to a recent Flash update and can be fixed by adding a crossdomain.xml file with three lines of code that detail a security policy. Doing anything like this with security policy files concerns me and I don't want to open up our site to any potential risks. So, can anyone here explain this in a way that makes me feel safe about adding a crossdomain.xml file to fix this Firefox error?

 

Well, it shouldn't be related to Firefox only. It's Flash feature.

Basically, in previous Flash versions, a swf file could access all domains and subdomains.
In new Flash versions it can access only a domain or a subdomain where the swf file resides.

When you want it to access a subdomain or completely different domain, it is required that there is crossdomain.xml file present which allows the swf file to access it.

So, it's useful e.g. for content owners/providers who only want some data to be accessible by partner websites only.

 

It shouldn't, but it is. I've found a discussion where others have noticed this as well. Try a Google search for "firefox flash permission denied" and you'll see this discussed.

 

When I search for it, I get different search results than you do when you search for it.
I won't try to find out what discussion you're talking about.
So, if you want me to see it, just post a link to the given web page.

I told you what the crossdomain.xml file is for.
If you want me or anybody else to help you or try to help you with the error you have, you need to give us more information.
That is exact error message and link to a page where the error occurs.