diff --git a/sys/dev/disk/isp/isp_freebsd.c b/sys/dev/disk/isp/isp_freebsd.c
--- a/sys/dev/disk/isp/isp_freebsd.c
+++ b/sys/dev/disk/isp/isp_freebsd.c
@@ -1923,8 +1923,8 @@
 	}
 
 	atiop->init_id = GET_IID_VAL(aep->at_iid);
-	atiop->cdb_len = aep->at_cdblen;
-	ISP_MEMCPY(atiop->cdb_io.cdb_bytes, aep->at_cdb, aep->at_cdblen);
+	atiop->cdb_len = min(aep->at_cdblen, sizeof(atiop->cdb_io.cdb_bytes));
+	ISP_MEMCPY(atiop->cdb_io.cdb_bytes, aep->at_cdb, atiop->cdb_len);
 	atiop->ccb_h.status = CAM_CDB_RECVD;
 	/*
 	 * Construct a tag 'id' based upon tag value (which may be 0..255)