JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<div class="container">

  <button type="button" class="btn btn-info btn-lg" data-toggle="modal" data-target="#myModal">Open Modal</button>

  <div class="modal fade" id="myModal" role="dialog">
    <div class="modal-dialog">
    
      <div class="modal-content">
        <div class="modal-header">
          <button type="button" class="close" data-dismiss="modal">&times;</button>
          <h4 class="modal-title">Modal Header</h4>
        </div>
        <div class="modal-body">
          <div class="row">
          <div class="col-md-8 col-ld-8 col-xs-8">
            11one  one  one  one  one  one  one  one 
            
          </div>
           <div class="col-md-4 col-ld-4 col-xs-4">
           <div style="width: 100%; height: 100px; overflow-y: scroll; overflow-x: hidden">
           22two  <br/> two <br/>  two  <br/> two  <br/> two <br/>  two <br/>  two  two  two
           </div><div>
           
           </div>
           </div>
           </div>
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
        </div>
      </div>
      
    </div>
  </div>
  
</div>

CSS

/* .addScroll{
  overflow-y:auto;
} */
/* .modal-body{
 overflow-y:auto;
} */