diff --git a/sys/dev/ath/if_ath_alq.c b/sys/dev/ath/if_ath_alq.c
index 1ad13db5e75d..8ca53ae2c579 100644
--- a/sys/dev/ath/if_ath_alq.c
+++ b/sys/dev/ath/if_ath_alq.c
@@ -184,9 +184,11 @@ if_ath_alq_post(struct if_ath_alq *alq, uint16_t op, uint16_t len,
 	/*
 	 * Copy the payload _after_ the header field.
 	 */
-	memcpy(((char *) ap) + sizeof(struct if_ath_alq_hdr),
-	    buf,
-	    len);
+	if (buf != NULL) {
+		memcpy(((char *) ap) + sizeof(struct if_ath_alq_hdr),
+		    buf,
+		    len);
+	}
 
 	alq_post(alq->sc_alq_alq, ale);
 }