Its actually a small bowl with a lid - the glass just lookes pretty thin. Ok, well its going in the oven soon. So if you see me posting later " How do I remove flying glass shards from the cat?" then you will know if it was ok or not........
If you wan't me to get technical......I suggest you get the cat out of the way while the shards are still flying and before they become imbedded in the cat....
I have been using Pyrex in ovens and microwaves for decades. The word "PYR" in Greek means fire, so it means Fireproof. (But not if you leave it on a gas ring, as I found out to my cost some time ago. ) Also, there is a very very rare chance that the Pyrex might have been made with a fault ( a bubble in the glass ) which swells in the microwave and shatters the item into hundreds of pieces. Happened to me with a tea-plate, but that must have been one incident in many thousand.
If it is 'Pyrex' brand then they should be ovenproof but never put them on the top of cooker as my husband did and it exploded, smashed and went into splinters everywhere. Can't trust him to be on his own. (I was on holiday when I got a phone call).
To DJH above: Plastic pyrex dishes? Not possible. Pyrex is, by definition, borosilicate glass and can withstand quick temperature changes eg out of hot oven and into cold water with no problem.
As a wedding present years ago I received a set of pyroflam dishes, They can go in the oven or on a gas or electric hob. Still going strong after all these years.