The remote host is missing an update to sympa announced via advisory DSA 2477-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%202477-1

Several vulnerabilities have been discovered in Sympa, a mailing list manager, that allow to skip the scenario-based authorization mechanisms. This vulnerability allows to display the archives management page, and download and delete the list archives by unauthorized users. For the stable distribution (squeeze), this problem has been fixed in version 6.0.1+dfsg-4+squeeze1. For the testing distribution (wheezy), this problem will be fixed soon. For the unstable distribution (sid), this problem has been fixed in version 6.1.11~dfsg-2. We recommend that you upgrade your sympa packages.