The remote host is missing an update to gnupg announced via advisory DSA 978-1. Tavis Ormandy noticed that gnupg, the GNU privacy guard - a free PGP replacement, verifies external signatures of files successfully even though they don't contain a signature at all. For the old stable distribution (woody) this problem has been fixed in version 1.0.6-4woody4.

For the stable distribution (sarge) this problem has been fixed in version 1.4.1-1sarge1. For the unstable distribution (sid) this problem will be fixed soon. We recommend that you upgrade your gnupg package. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20978-1