The remote host is vulnerable to a Denial of Service (DoS) attack.
The remote host is running ClamAV, an open-source antivirus solution for Unix-like systems. This version of ClamAV is reported to be vulnerable to a flaw where the parsing of a malicious file will cause the ClamAV process to crash. An attacker exploiting this flaw would need to be able to send a specially formed email to the system running ClamAV. Successful exploitation would result in loss of service.
Upgrade to version 0.86.1 or higher.