The remote host is missing an update to sendmail-wide announced via advisory DSA 290-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20290-1

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+3.5Wbeta-5.4 For the old stable distribution (potato) this problem has been fixed in version 8.9.3+3.2W-25 For the unstable distribution (sid) this problem has been fixed in version 8.12.9+3.5Wbeta-1 We recommend that you upgrade your sendmail-wide packages.