The remote host is missing an update to clamav announced via advisory DSA 1232-1. Stephen Gran discovered that malformed base64-encoded MIME attachments can lead to denial of service through a null pointer dereference.

For the stable distribution (sarge) this problem has been fixed in version 0.84-2.sarge.12. For the upcoming stable distribution (etch) this problem has been fixed in version 0.86-1. For the unstable distribution (sid) this problem has been fixed in version 0.86-1. We recommend that you upgrade your clamav package. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201232-1