diff --git a/lib/memcached.js b/lib/memcached.js
index 761b299..a8941af 100644
--- a/lib/memcached.js
+++ b/lib/memcached.js
@@ -516,8 +516,15 @@ Client.config = {
 
       switch (flag) {
         case FLAG_JSON:
-          dataSet = JSON.parse(dataSet);
-          break;
+            try {
+                dataSet = JSON.parse(dataSet);
+                break;
+            } catch (err) {
+                dataSet = null;
+                err.push(new Error('error during JSON parsing'));
+                break;
+            }
+          
         case FLAG_NUMERIC:
           dataSet = +dataSet;
           break;
@@ -801,6 +808,15 @@ Client.config = {
       // check if we need to remove an empty item from the array, as splitting on /r/n might cause an empty
       // item at the end..
       if (S.bufferArray[0] === '') S.bufferArray.shift();
+
+      while (S.bufferArray.length){
+        if(!privates.allCommands.test(S.bufferArray[0])) {
+          err.push(new Error('unknown command in memcache data'));
+          S.bufferArray.shift();
+        } else {
+          break;
+        }
+      }
     }
   };