Index: madwifi-ng-r2568-20070710/ath/if_ath.c
===================================================================
--- madwifi-ng-r2568-20070710.orig/ath/if_ath.c	2007-07-13 09:14:14.721154018 +0200
+++ madwifi-ng-r2568-20070710/ath/if_ath.c	2007-07-13 09:14:55.499477843 +0200
@@ -5711,8 +5711,9 @@
 			/*
 			 * Reject error frames if we have no vaps that 
 			 * are operating in monitor mode.
+			 * Reject empty frames as well
 			 */
-			if (sc->sc_nmonvaps == 0)
+			if ((sc->sc_nmonvaps == 0) || (rs->rs_datalen == 0))
 				goto rx_next;
 		}
 rx_accept: