diff --git a/apps/calendar/ajax/share/changepermission.php b/apps/calendar/ajax/share/changepermission.php
index e807c164a236926b3a66fc2513cafae661a3c523..5aff7666f79449fd7b9f625be2a59cb36363b5f0 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 838db619f62c55d36bed3cfe1ee87d6b959109f3..77e1ab9d657efa8a0bd0bf4bcb32b4a209d4b0f7 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 1ce04677fb13c3c1bf37f2ec0f8240b099b3c883..c7c0611318918b387da3bfab9f54bb9f0b5fbe2d 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){