The remote host is missing an update to sendmail announced via advisory DSA 278-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20278-1

Michal Zalewski discovered a buffer overflow, triggered by a char to int conversion, in the address parsing code in sendmail, a widely used powerful, efficient, and scalable mail transport agent. This problem is potentially remotely exploitable. For the stable distribution (woody) this problem has been fixed in version 8.12.3-6.2. For the stable distribution (woody) this problem has been fixed in version 8.9.3-26. For the unstable distribution (sid) this problem has been fixed in version 8.12.9-1. We recommend that you upgrade your sendmail packages.