ClamAV AntiVirus software versions 0.99.2 and prior contain a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or potentially execute arbitrary code on an affected device. The vulnerability is due to improper input validation checking mechanisms in mew packet files sent to an affected device. A successful exploit could cause a heap-based buffer over-read condition in mew.c when ClamAV scans the malicious file, allowing the attacker to cause a DoS condition or potentially execute arbitrary code on the affected device.
https://usn.ubuntu.com/3550-2/
https://usn.ubuntu.com/3550-1/
https://lists.debian.org/debian-lts-announce/2018/01/msg00035.html
http://blog.clamav.net/2018/01/clamav-0993-has-been-released.html