diff --git a/apps/calendar/ajax/share/changepermission.php b/apps/calendar/ajax/share/changepermission.php
index e807c164a2..5aff7666f7 100644
--- a/apps/calendar/ajax/share/changepermission.php
+++ b/apps/calendar/ajax/share/changepermission.php
@@ -5,7 +5,9 @@
  * later.
  * See the COPYING-README file.
  */
- 
+
+OCP\JSON::callCheck();
+
 $id = strip_tags($_POST['id']);
 $idtype = strip_tags($_POST['idtype']);
 $permission = (int) strip_tags($_POST['permission']);
diff --git a/apps/calendar/ajax/share/share.php b/apps/calendar/ajax/share/share.php
index 838db619f6..77e1ab9d65 100644
--- a/apps/calendar/ajax/share/share.php
+++ b/apps/calendar/ajax/share/share.php
@@ -6,6 +6,8 @@
  * See the COPYING-README file.
  */
  
+OCP\JSON::callCheck();
+
 $id = strip_tags($_POST['id']);
 $idtype = strip_tags($_POST['idtype']);
 switch($idtype){
diff --git a/apps/calendar/ajax/share/unshare.php b/apps/calendar/ajax/share/unshare.php
index 1ce04677fb..c7c0611318 100644
--- a/apps/calendar/ajax/share/unshare.php
+++ b/apps/calendar/ajax/share/unshare.php
@@ -5,7 +5,9 @@
  * later.
  * See the COPYING-README file.
  */
- 
+
+OCP\JSON::callCheck();
+
 $id = strip_tags($_POST['id']);
 $idtype = strip_tags($_POST['idtype']);
 switch($idtype){