As noted, the user uses the term "bricks", incorrectly. With the exception of one player on the team, who had his messages set to private, everyone on the team was forced to factory reset their PS4s to regain functionality. Multiple users have discussed the issue on the r/PS4 Reddit forum, where they say they are receiving messages through with suspicious characters, that has locked them out of games, and eventually, off their PlayStation entirely.
The main advice though is to change the messaging options on the console so you only receive messages from friends or no one. Options for that setting include allowing messages from anyone, friends only, or no one.
Reddit users seemed to all have stories beginning similarly with "I was beating these guys in x online game" before they received the message.
And you don't even have to open the message for it to happen like your conventional email-spread malware. We're not totally clued up on the technical details yet, but the bottom line is that right now, a factory reset of your PS4 - which deletes all of your data - is the only guaranteed way to get your console up and running again.
Thankfully, you can do that from the PSN web interface or the mobile apps for Android and iOS so you needn't risk bricking your machine just to turn messaging off. "Messages" and then Messages.
So if your messaging settings currently allow you to receive messages from strangers, you may want to change them for now. As a reminder, Sony has disabled the ability to send the offending characters, so it's unlikely anyone will be affected from here on out.