The remote host is missing an update to linpopup announced via advisory DSA 632-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20632-1

Stephen Dranger discovered a buffer overflow in linpopup, an X11 port of winpopup, running over Samba, that could lead to the execution of arbitrary code when displaying a maliciously crafted message. For the stable distribution (woody) this problem has been fixed in version 1.2.0-2woody1. For the unstable distribution (sid) this problem has been fixed in version 1.2.0-7. We recommend that you upgrade your linpopup package.