An exploitable heap out of bounds write vulnerability exists in the Fitz graphical library part of the MuPDF renderer. A specially crafted PDF file can cause a out of bounds write resulting in heap metadata and sensitive process memory corruption leading to potential code execution. Victim needs to open the specially crafted file in a vulnerable reader in order to trigger this vulnerability.
https://www.talosintelligence.com/vulnerability_reports/TALOS-2016-0242
https://bugs.ghostscript.com/show_bug.cgi?id=697395
http://www.ghostscript.com/cgi-bin/findgit.cgi?0c86abf954ca4a5f00c26f6600acac93f9fc3538