In BlueZ 5.42, a buffer over-read was identified in "l2cap_packet" function in "monitor/packet.c" source file. This issue can be triggered by processing a corrupted dump file and will result in btmon crash.
https://www.spinics.net/lists/linux-bluetooth/msg68898.html
https://euvd.enisa.europa.eu/vulnerability/EUVD-2016-10603
http://www.securityfocus.com/bid/94652
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00069.html