The remote host is missing an update to xulrunner announced via advisory DSA 1756-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201756-1

Several remote vulnerabilities have been discovered in Xulrunner, a runtime environment for XUL applications, such as the Iceweasel web browser. The Common Vulnerabilities and Exposures project identifies the following problems: CVE-2009-1169 Security researcher Guido Landi discovered that a XSL stylesheet could be used to crash the browser during a XSL transformation. An attacker could potentially use this crash to run arbitrary code on a victim's computer. CVE-2009-1044 Security researcher Nils reported via TippingPoint's Zero Day Initiative that the XUL tree method _moveToEdgeShift was in some cases triggering garbage collection routines on objects which were still in use. In such cases, the browser would crash when attempting to access a previously destroyed object and this crash could be used by an attacker to run arbitrary code on a victim's computer. Note that after installing these updates, you will need to restart any packages using xulrunner, typically iceweasel or epiphany. For the stable distribution (lenny), these problems have been fixed in version 1.9.0.7-0lenny2. As indicated in the Etch release notes, security support for the Mozilla products in the oldstable distribution needed to be stopped before the end of the regular Etch security maintenance life cycle. You are strongly encouraged to upgrade to stable or switch to a still supported browser. For the unstable distribution (sid), these problems have been fixed in version 1.9.0.8-1 We recommend that you upgrade your xulrunner package.