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.
An exploitable memory corruption vulnerability exists in the JBIG2 parser of Artifex MuPDF 1.9. A specially crafted PDF can cause a negative number to be passed to a memset resulting in memory corruption and potential code execution. An attacker can specially craft a PDF and send to the victim to trigger this vulnerability.
These are old, but filing just in case. No links to any fix in the
reports. Asked in #mupdf on libera.chat about them.
CVE-2016-8729 does not apply to us because we don't use the bundled version and looking at upstream git they also stopped using it.
CVE-2016-8728 appears not to be fixed yet.