The remote host is missing an update to horde3 announced via advisory DSA 2278-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202278-1

It was discovered that horde3, the horde web application framework, is prone to a cross-site scripting attack and a cross-site request forgery. For the oldstable distribution (lenny), these problems have been fixed in version 3.2.2+debian0-2+lenny3. For the stable distribution (squeeze), these problems have been fixed in version 3.3.8+debian0-2, which was already included in the squeeze release. For the testing distribution (wheezy) and the unstable distribution (sid), these problems have been fixed in version 3.3.8+debian0-2. We recommend that you upgrade your horde3 packages.