The remote host is missing an update to ikiwiki announced via advisory DSA 1875-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%201875-1

Josh Triplett discovered that the blacklist for potentially harmful TeX code of the teximg module of the Ikiwiki wiki compiler was incomplete, resulting in information disclosure. The old stable distribution (etch) is not affected. For the stable distribution (lenny), this problem has been fixed in version 2.53.4. For the unstable distribution (sid), this problem has been fixed in version 3.1415926. We recommend that you upgrade your ikiwiki package.