The remote host is missing an update to clamav announced via advisory USN-756-1.

The problem can be corrected by upgrading your system to the following package versions: Ubuntu 8.10: libclamav5 0.94.dfsg.2-1ubuntu0.3 In general, a standard system upgrade is sufficient to effect the necessary changes. https://secure1.securityspace.com/smysecure/catid.html?in=USN-756-1

It was discovered that ClamAV did not properly verify buffers when processing Upack files. A remote attacker could send a crafted file and cause a denial of service via application crash.