Artifex Ghostscript through 2017-04-26 allows -dSAFER bypass and remote command execution via .rsdparams type confusion with a "/OutputFile (%pipe%" substring in a crafted .eps document that is an input to the gs program, as exploited in the wild in April 2017.
The .sethalftone5 function in psi/zht2.c in Ghostscript before 9.21 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted Postscript document that calls .sethalftone5 with an empty operand stack.