diff -up radvd-1.8.2/device-linux.c.iface radvd-1.8.2/device-linux.c
--- radvd-1.8.2/device-linux.c.iface	2011-10-10 10:26:47.089760082 +0200
+++ radvd-1.8.2/device-linux.c	2011-10-10 10:27:12.149014098 +0200
@@ -244,7 +244,7 @@ set_interface_var(const char *iface,
 		return -1;
 
 	/* No path traversal */
-	if (strstr(name, "..") || strchr(name, '/'))
+	if (!iface[0] || !strcmp(iface, ".") || !strcmp(iface, "..") || strchr(iface, '/'))
 		return -1;
 
 	if (access(spath, F_OK) != 0)