The remote host is missing an update to gdm3 announced via advisory DSA 2205-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202205-1

Sebastian Krahmer discovered that the gdm3, the GNOME Desktop Manager, does not properly drop privileges when manipulating files related to the logged-in user. As a result, local users can gain root privileges. The oldstable distribution (lenny) does not contain a gdm3 package. The gdm package is not affected by this issue. For the stable distribution (squeeze), this problem has been fixed in version 2.30.5-6squeeze2. For the testing distribution (wheezy) and the unstable distribution (sid), this problem will be fixed soon. We recommend that you upgrade your gdm3 packages.