The Color Curve Tool from Premiere CC cuts off luminance to 100% video level. That is a problem if the input videos have so-called "super-whites" in it.
This would include for example the Canon C100, C300, C500 because the video levels from this cameras defaults to more then 100% video-level.
The Curve Tool was definetly not clipping at 100% in Premiere CS6!
Please consider this as a bug that has to be fixed soon, because it changes colors all older projects which includes material from this popular cameras.
BTW - Speedgrade CC (also previous versions) also did not handle Super-Whites correctly and clips it even at import! This does not seemed to be fixed in SG CC.
Yes, we know about that one. Feel free to file a bug report: http://www.adobe.com/go/wish