The remote host is missing an update to tor announced via advisory DSA 2148-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202148-1

The developers of Tor, an anonymizing overlay network for TCP, found three security issues during a security audit. A heap overflow allowed the execution of arbitrary code (CVE-2011-0427), a denial of service vulnerability was found in the zlib compression handling and some key memory was incorrectly zeroed out before being freed. The latter two issues do not yet have CVE identifiers assigned. The Debian Security Tracker will be updated once they're available: http://security-tracker.debian.org/tracker/source-package/tor For the stable distribution (lenny), this problem has been fixed in version 0.2.1.29-1~lenny+1. For the testing distribution (squeeze) and the unstable distribution (sid), this problem has been fixed in version 0.2.1.29-1. For the experimental distribution, this problem has been fixed in version 0.2.2.21-alpha-1. We recommend that you upgrade your tor packages.