The remote host is missing an update to icedove announced via advisory DSA 2235-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202235-1

Several vulnerabilities have been discovered in Icedove, an unbranded version of the Thunderbird mail/news client. CVE-2011-0069 CVE-2011-0070 CVE-2011-0072 CVE-2011-0074 CVE-2011-0075 CVE-2011-0077 CVE-2011-0078 CVE-2011-0080 CVE-2011-0081 Scoobidiver, Ian Beer Bob Clary, Henri Sivonen, Marco Bonardo, Mats Palmgren, Jesse Ruderman, Aki Kelin and Martin Barbella discovered memory corruption bugs, which may lead to the execution of arbitrary code. CVE-2011-0065 CVE-2011-0066 CVE-2011-0073 regenrecht discovered several dangling pointer vulnerabilities, which may lead to the execution of arbitrary code. CVE-2011-0067 Paul Stone discovered that Java applets could steal information from the autocompletion history. CVE-2011-0071 Soroush Dalili discovered a directory traversal vulnerability in handling resource URIs. As indicated in the Lenny (oldstable) release notes, security support for the Icedove packages in the oldstable needed to be stopped before the end of the regular Lenny security maintenance life cycle. You are strongly encouraged to upgrade to stable or switch to a different mail client. For the stable distribution (squeeze), this problem has been fixed in version 3.0.11-1+squeeze2. For the unstable distribution (sid), this problem will be fixed soon. We recommend that you upgrade your icedove packages.