diff --git a/lib/codemirror.js b/lib/codemirror.js
index f0f8837aed1919977b46e7f7d5a0a2dd11a6ca7f..1fd68dda24a86ccf18b5d100eb6fd3a73be8d573 100644
--- a/lib/codemirror.js
+++ b/lib/codemirror.js
@@ -3827,7 +3827,9 @@
 
         var reader = new FileReader;
         reader.onload = operation(cm, function() {
-          text[i] = reader.result;
+          var content = reader.result;
+          if (/[\x00-\x08\x0e-\x1f]{2}/.test(content)) content = "";
+          text[i] = content;
           if (++read == n) {
             pos = clipPos(cm.doc, pos);
             var change = {from: pos, to: pos,