diff --git a/bundles/AdminBundle/Controller/Admin/DataObject/ClassController.php b/bundles/AdminBundle/Controller/Admin/DataObject/ClassController.php
index ce44ed65340..58959ce1cba 100644
--- a/bundles/AdminBundle/Controller/Admin/DataObject/ClassController.php
+++ b/bundles/AdminBundle/Controller/Admin/DataObject/ClassController.php
@@ -455,6 +455,14 @@ public function saveAction(Request $request)
             $class->rename($values['name']);
         }
 
+        if ($values['compositeIndices']) {
+            foreach ($values['compositeIndices'] as $index => $compositeIndex) {
+                if ($compositeIndex['index_key'] !== ($sanitizedKey = preg_replace('/[^a-za-z0-9_\-+]/', '', $compositeIndex['index_key']))) {
+                    $values['compositeIndices'][$index]['index_key'] = $sanitizedKey;
+                }
+            }
+        }
+
         unset($values['creationDate']);
         unset($values['userOwner']);
         unset($values['layoutDefinitions']);
diff --git a/bundles/AdminBundle/Resources/public/js/pimcore/object/classes/class.js b/bundles/AdminBundle/Resources/public/js/pimcore/object/classes/class.js
index 28602a94fda..ebedbe757d2 100644
--- a/bundles/AdminBundle/Resources/public/js/pimcore/object/classes/class.js
+++ b/bundles/AdminBundle/Resources/public/js/pimcore/object/classes/class.js
@@ -1085,7 +1085,14 @@ pimcore.object.classes.klass = Class.create({
             fieldLabel: t("key"),
             labelWidth: 100,
             width: 250,
-            value: data.index_key
+            value: data.index_key,
+            validator: function (value) {
+                if(value !== value.replace(/[^a-za-z0-9_\-+]/g,'')){
+                    this.setvalue(value.replace(/[^a-za-z0-9_\-+]/g,''));
+                }
+
+                return true;
+            }
         };
 
         //fixes data to match store model