The generally accepted industry standard for ALL computer media is 125'F. That's a max temp, and it should be noted that the longer the media is exposed to this temp, the lower the max is. I'd say that 100'F would be a fair bet for short-term exposure. Humidity is also a factor.
My media vault is rated to maintain under 125' for one hour in a 2000'F fire. I don't plan on testing it. I keep CDRs in my car in the southwest USA desert all year, I'm sure temps routinely hit 100, so far no big problems.