The remote host is missing an update to gnupg announced via advisory DSA 993-1. Tavis Ormandy noticed that gnupg, the GNU privacy guard - a free PGP replacement, can be tricked to emit a good signature status message when a valid signature is included which does not belong to the data packet. The old stable distribution (woody) is not affected by this problem.

For the stable distribution (sarge) this problem has been fixed in version 1.4.1-1.sarge3. For the unstable distribution (sid) this problem has been fixed in version 1.4.2.2-1. We recommend that you upgrade your gnupg package. https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20993-1