This command line gives a segfault:

cat out.pdf | RIP_MAX_CACHE=128m gs -dNOPAUSE -sstdout=%stderr -sOutputFile=%stdout -sDEVICE=cups -r600x600 -dcupsBitsPerColor=8 -dcupsColorOrder=0 -dcupsColorSpace=4 -_ > out.raster

If I set 300 dpi resolution

cat out.pdf | RIP_MAX_CACHE=128m gs -dNOPAUSE -sstdout=%stderr -sOutputFile=%stdout -sDEVICE=cups -r300x300 -dcupsBitsPerColor=8 -dcupsColorOrder=0 -dcupsColorSpace=4 -_ > out.raster

I do not get a segfault but the output is scrambled (use Mike Sweet's rasterview to display).

If CUPS calls ghostscript it sets the RIP_MAX_CACHE=128m environment variable. If I do not set this variable, I get Ghostscript also not crashing with 600 dpi but the output is still scrambled:

cat out.pdf | gs -dNOPAUSE -sstdout=%stderr -sOutputFile=%stdout -sDEVICE=cups -r600x600 -dcupsBitsPerColor=8 -dcupsColorOrder=0 -dcupsColorSpace=4 -_ > out.raster

Selecting other cupsColorSpace values there is no problem (like 1 for RGB, 3, for Gray, 18, 19, 20 for SGRay, SRGB, and AdobeRGB).

So there are two bugs: CMY output is scrambled, and the segfault with the first command line.

Sample input file, out.pdf is attached.