PhpMyAdmin error: JSON extension is missing

Today I found out that my phpMyAdmin installation over apache2 and Ubuntu 13.10 was broken. The error was straight forward: “JSON extension is missing”.

Okay, but how can it be gone?

I recently updated my Ubuntu installation from 13.04 to 13.10. Turns out that it somehow breaks the PHP JSON extension.

The fix is very simple, run

sudo apt-get install php5-json
sudo service apache2 restart

Problem sovled.