The remote host is missing an update to tor announced via advisory DSA 2548-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202548-1

Severel vulnerabilities have been discovered in Tor, an online privacy tool. CVE-2012-3518 Avoid an uninitialised memory read when reading a vote or consensus document that has an unrecognized flavour name. This could lead to a remote, resulting in denial of service. CVE-2012-3519 Try to leak less information about what relays a client is choosing to a side-channel attacker. CVE-2012-4419 By providing specially crafted date strings to a victim tor instance, an attacker can cause it to run into an assertion and shut down Additionally the update to stable includes the following fixes: - - When waiting for a client to renegotiate, don't allow it to add any bytes to the input buffer. This fixes a potential DoS issue [tor-5934, tor-6007]. For the stable distribution (squeeze), these problems have been fixed in version 0.2.2.39-1. For the unstable distribution, these problems have been fixed in version 0.2.3.22-rc-1. We recommend that you upgrade your tor packages.