Maximum oven temperature for glass cookware
A glass casserole dish, with a casserole in it, will be safe at any temperature your oven can reach.

As Ring mentioned, the issue is not absolute temperature, but fast changes in temperature, leading to a temperature differential and thermal stresses inside the dish. Your oven cannot heat the dish fast enough to cause a problem, and the wet food inside will prevent the dish from going far above 100C, meaning that cooling it down afterwards will also be safe.

If you're using the dish to roast dry ingredients, or otherwise won't have food keeping the dish cool, it'll still be safe, but afterwards make sure to let it cool a bit before running cold water over it.

And remember the first rule for avoiding burns: HOT GLASS LOOKS LIKE COLD GLASS. Pay attention and don't pick it up with your bare hands once it's out of the oven.