The remote host is missing an update to mozilla-thunderbird announced via advisory DSA 868-1. Several security-related problems have been discovered in Mozilla and derived programs. Some of the problems don't exactly apply to Mozilla Thunderbird, even though the code is present. In order to keep the codebase in sync with upstream it has been altered nevertheless. For details on the problems, please visit the referenced security advisories.

For the stable distribution (sarge) these problems have been fixed in version 1.0.2-2.sarge1.0.7. For the unstable distribution (sid) these problems have been fixed in version 1.0.7-1. We recommend that you upgrade your mozilla-thunderbird package. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20868-1