The remote host is missing an update to libapreq2-perl announced via advisory DSA 1000-1. An algorithm weakness has been discovered in Apache2::Request, the generic request library for Apache2 which can be exploited remotely and cause a denial of service via CPU consumption. The old stable distribution (woody) does not contain this package.
For the stable distribution (sarge) this problem has been fixed in version 2.04-dev-1sarge1. For the unstable distribution (sid) this problem has been fixed in version 2.07-1. We recommend that you upgrade your libapreq2, libapache2-mod-apreq2 https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201000-1