The remote host is missing an update to sudo announced via advisory DSA 596-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20596-1

Liam Helmer noticed that sudo, a program that provides limited super user privileges to specific users, does not clean the environment sufficiently. Bash functions and the CDPATH variable are still passed through to the program running as privileged user, leaving possibilities to overload system routines. These vulnerabilities can only be exploited by users who have been granted limited super user privileges. For the stable distribution (woody) these problems have been fixed in version 1.6.6-1.2. For the unstable distribution (sid) these problems have been fixed in version 1.6.8p3. We recommend that you upgrade your sudo package.