XF 2.3 Security Error Notice

[wedgar]

Within the past week or so, I have seen a security error notice pop-up when reading through unread message on this site.

Nothing explains the security error or what needs to be avoided.

What is the security error?

 

[Digital Doctor]

I got this error today on a Xenforo forum.

on the media tab,
it shows another person's account information.

and the error comes up when I try to click any of the 3 links.