Aircraft have been overpressurised when being tested (due to maintainer error/neglect), like
this KC 135:
But I've only ever seen this kind of damage when the pressure came from an external source during testing. Whilst never suggesting it's completely impossible, I'd be surprised to discover any significant over-pressurisation from the internal cabin pressurisation system. You'd have to line up a heck of a lot of very dumb holes in the cheese slices for that to happen.
Originally Posted by HappyPass
Like, 4 bar cabin pressure, enough to cause damage to the inner ear.
On a point of order - being in a pressurised chamber at 4bar won't necessarily damage the inner ear. Any scuba diver who goes down to the 120ft level exposes his/her ears to that sort of pressure. Sudden changes inb pressure would be a different matter, but to be honest if you're in a chamber at 150psi when someone opens the door your inner ear is probably one of your more mninor concerns...
PDR