The remote host is missing an update to iceweasel announced via advisory DSA 2186-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202186-1

Several vulnerabilities have been discovered in Iceweasel, a web browser based on Firefox. The included XULRunner library provides rendering services for several other applications included in Debian. CVE-2010-1585 Roberto Suggi Liverani discovered that the sanitising performed by ParanoidFragmentSink was incomplete. CVE-2011-0053 Crashes in the layout engine may lead to the execution of arbitrary code. CVE-2011-0051 Zach Hoffmann discovered that incorrect parsing of recursive eval() calls could lead to attackers forcing acceptance of a confirmation dialogue. CVE-2011-0054, CVE-2010-0056 Christian Holler discovered buffer overflows in the Javascript engine, which could allow the execution of arbitrary code. CVE-2011-0055 regenrecht and Igor Bukanov discovered a use-after-free error in the JSON-Implementation, which could lead to the execution of arbitrary code. CVE-2011-0057 Daniel Kozlowski discovered that incorrect memory handling the web workers implementation could lead to the execution of arbitrary code. CVE-2011-0059 Peleus Uhley discovered a cross-site request forgery risk in the plugin code. For the oldstable distribution (lenny), this problem has been fixed in version 1.9.0.19-8 of the xulrunner source package. For the stable distribution (squeeze), this problem has been fixed in version 3.5.16-5. For the unstable distribution (sid), this problem has been fixed in version 3.5.17-1. We recommend that you upgrade your iceweasel packages.