The remote host is missing an update to php5 announced via advisory DSA 2403-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202403-1

Stefan Esser discovered that the implementation of the max_input_vars configuration variable in a recent PHP security update was flawed such that it allows remote attackers to crash PHP or potentially execute code. For the oldstable distribution (lenny), no fix is available at this time. For the stable distribution (squeeze), this problem has been fixed in version 5.3.3-7+squeeze7. The testing distribution (wheezy) and unstable distribution (sid) will be fixed soon. We recommend that you upgrade your php5 packages.