diff --git a/src/com/android/messaging/ui/mediapicker/DocumentImagePicker.java b/src/com/android/messaging/ui/mediapicker/DocumentImagePicker.java
index 2c36752..bb267da 100644
--- a/src/com/android/messaging/ui/mediapicker/DocumentImagePicker.java
+++ b/src/com/android/messaging/ui/mediapicker/DocumentImagePicker.java
@@ -24,6 +24,8 @@
 import com.android.messaging.Factory;
 import com.android.messaging.datamodel.data.PendingAttachmentData;
 import com.android.messaging.ui.UIIntents;
+import com.android.messaging.util.LogUtil;
+import com.android.messaging.util.FileUtil;
 import com.android.messaging.util.ImageUtils;
 import com.android.messaging.util.SafeAsyncTask;
 
@@ -111,12 +113,23 @@
         new SafeAsyncTask<Void, Void, String>() {
             @Override
             protected String doInBackgroundTimed(final Void... params) {
+                if (FileUtil.isInPrivateDir(documentUri)) {
+                    // hacker sending private app data. Bail out
+                    if (LogUtil.isLoggable(LogUtil.BUGLE_TAG, LogUtil.ERROR)) {
+                        LogUtil.e(LogUtil.BUGLE_TAG, "Aborting attach of private app data ("
+                                + documentUri + ")");
+                    }
+                    return null;
+                }
                 return ImageUtils.getContentType(
                         Factory.get().getApplicationContext().getContentResolver(), documentUri);
             }
 
             @Override
             protected void onPostExecute(final String contentType) {
+                if (contentType == null) {
+                    return;     // bad uri on input
+                }
                 // Ask the listener to create a temporary placeholder item to show the progress.
                 final PendingAttachmentData pendingItem =
                         PendingAttachmentData.createPendingAttachmentData(contentType,