The remote host is missing an update to exim-tls announced via advisory DSA 502-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20502-1

Georgi Guninski discovered two stack-based buffer overflows in exim and exim-tls. They can not be exploited with the default configuration from the Debian system, though. The Common Vulnerabilities and Exposures project identifies the following problems that are fixed with this update: CVE-2004-0399 When sender_verify = true is configured in exim.conf a buffer overflow can happen during verification of the sender. This problem is fixed in exim 4. CVE-2004-0400 When headers_check_syntax is configured in exim.conf a buffer overflow can happen during the header check. This problem does also exist in exim 4. For the stable distribution (woody) these problems have been fixed in version 3.35-3woody2. The unstable distribution (sid) does not contain exim-tls anymore. The functionality has been incorporated in the main exim versions which have these problems fixed in version 3.36-11 for exim 3 and in version 4.33-1 for exim 4. We recommend that you upgrade your exim-tls package.