But Sony has since issued a fix. As its UK support Twitter feed states, PS4 consoles should be updated to ensure the exploit no longer works:
We've since fixed the issue, and it wasn't bricking consoles, just sending them into a crash loop that can be quickly fixed in under 5 minutes. Delete the message on the PS mobile app, go into Safe Mode, use Option 5, console back to normal. ^DB— Ask PlayStation UK (@AskPS_UK) October 15, 2018
The issue arose when a fair few posters on Reddit claimed they had received such a message, which subsequently bricked their machines. And the only way to get it working again was to factory reset the console - losing all installations and locally stored save games in the process.
Some also reported that messages can be sent to entire groups of players too, which forces the entire team to reset their consoles.
Now that Sony has issue the fix, however, you should be fine. But if you haven't yet received the update or are worries about future exploits being found, here is a way to prevent exploit messages affecting your console.
How to avoid being sent the PS4 exploit?
If exploits are discovered again, you can take steps to prevent the messages coming through.
The first is to ensure that you set your incoming messages to enable just friends to contact you or no one at all.
The PS4 default is to allow anyone to message you so you need to head here to change it: Settings > Account Management > Privacy Settings > Personal Info/Messaging > Messages and change the drop-down both to either "Friends Only" or "No One". Hit "Confirm".
Of course, if you select "Friends Only" you are still open to attack from anyone in your friends list, but hopefully that doesn't include any idiots.
You can view an exploit message in the app too and it won't break your phone, then follow the alternative steps in the tweet above.
We're not publishing the original attack message details as that might encourage others to try it out.