diff --git a/inc/field/dropdownfield.class.php b/inc/field/dropdownfield.class.php
index 5fb5f92cd..13ddc280e 100644
--- a/inc/field/dropdownfield.class.php
+++ b/inc/field/dropdownfield.class.php
@@ -594,7 +594,7 @@ private function getMyGroups($userID) {
    }
 
    public function equals($value): bool {
-      $value = html_entity_decode($value);
+      $value = html_entity_decode($value ?? '');
       $itemtype = $this->question->fields['itemtype'];
       $dropdown = new $itemtype();
       if ($dropdown->isNewId($this->value)) {
@@ -616,7 +616,7 @@ public function notEquals($value): bool {
    }
 
    public function greaterThan($value): bool {
-      $value = html_entity_decode($value);
+      $value = html_entity_decode($value ?? '');
       $itemtype = $this->question->fields['itemtype'];
       $dropdown = new $itemtype();
       if (!$dropdown->getFromDB($this->value)) {
@@ -635,7 +635,7 @@ public function lessThan($value): bool {
    }
 
    public function regex($value): bool {
-      $value = html_entity_decode($value);
+      $value = html_entity_decode($value ?? '');
       $itemtype = $this->question->fields['itemtype'];
       $dropdown = new $itemtype();
       if (!$dropdown->getFromDB($this->value)) {
diff --git a/inc/field/glpiselectfield.class.php b/inc/field/glpiselectfield.class.php
index 8450f7e8d..71a1f67dd 100644
--- a/inc/field/glpiselectfield.class.php
+++ b/inc/field/glpiselectfield.class.php
@@ -160,7 +160,7 @@ public function buildParams($rand = null) {
    }
 
    public function equals($value): bool {
-      $value = html_entity_decode($value);
+      $value = html_entity_decode($value ?? '');
       $itemtype = $this->getSubItemtype();
       $item = new $itemtype();
       if ($item->isNewId($this->value)) {
@@ -177,7 +177,7 @@ public function notEquals($value): bool {
    }
 
    public function greaterThan($value): bool {
-      $value = html_entity_decode($value);
+      $value = html_entity_decode($value ?? '');
       $itemtype = $this->getSubItemtype();
       $item = new $itemtype();
       if (!$item->getFromDB($this->value)) {