The remote host is missing an update to clamav announced via advisory DSA 1050-1. Ulf Härnhammar and an anonymous researcher from Germany discovered a vulnerability in the protocol code of freshclam, a command line utility responsible for downloading and installing virus signature updates for ClamAV, the antivirus scanner for Unix. This could lead to a denial of service or potentially the execution of arbitrary code. The old stable distribution (woody) does not contain clamav packages.
For the stable distribution (sarge) this problem has been fixed in version 0.84-2.sarge.9. For the unstable distribution (sid) this problem has been fixed in version 0.88.2-1. We recommend that you upgrade your clamav packages. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201050-1