The remote host is missing an update to autorespond announced via advisory DSA 373-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20373-1

Christian Jaeger discovered a buffer overflow in autorespond, an email autoresponder used with qmail. This vulnerability could potentially be exploited by a remote attacker to gain the privileges of a user who has configured qmail to forward messages to autorespond. This vulnerability is currently not believed to be exploitable due to incidental limits on the length of the problematic input, but there may be situations in which these limits do not apply. For the stable distribution (woody) this problem has been fixed in version 2.0.2-2woody1. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you update your autorespond package.