The remote host is missing an update to sendmail announced via advisory DSA 278-2.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20278-2

This is a major brown paperbag update. The old packages for the stable distribution (woody) did not work as expected and you should only update to the neww packages mentioned in this advisory. The packages in the old stable distribution (potato) are working properly. I'm awfully sorry for the inconvenience. At the moment updated packages are only available for alpha, i386 and sparc. The original advisory was: 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 8.12.3-6.3. We recommend that you upgrade your sendmail packages.