The remote host is missing updates announced in advisory TSLSA-2006-0072.
clamav < TSL 3.0 > < TSL 2.2 > - New Upstream. - SECURITY Fix: Hendrik Weimer has reported a vulnerability in ClamAV, which can be exploited by malicious people to cause a DoS (Denial of Service). The vulnerability is caused due to a stack overflow when scanning messages with deeply nested multipart content. This can be exploited to crash the service by sending specially crafted emails to a vulnerable system.
The Common Vulnerabilities and Exposures project has assigned the name CVE-2006-6481 to this issue.
Solution: Update your system with the packages as indicated in the referenced security advisory.