--- /dev/null
+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: