The remote host is missing an update to heartbeat announced via advisory DSA 1128-1. Yan Rong Ge discovered that wrong permissions on a shared memory page in heartbeat, the subsystem for High-Availability Linux could be exploited by a local attacker to cause a denial of service.
For the stable distribution (sarge) this problem has been fixed in version 1.2.3-9sarge5. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you upgrade your heartbeat packages. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201128-1