diff --git a/phpBB/config/services.yml b/phpBB/config/services.yml
index 8f58d23fd9..dc293c83a2 100644
--- a/phpBB/config/services.yml
+++ b/phpBB/config/services.yml
@@ -173,7 +173,7 @@ services:
         class: phpbb_hook_finder
         arguments:
             - %core.root_path%
-            - .%core.php_ext%
+            - %core.php_ext%
             - @cache.driver
 
     kernel_request_subscriber:
diff --git a/phpBB/includes/hook/finder.php b/phpBB/includes/hook/finder.php
index 065e685514..7b0412f733 100644
--- a/phpBB/includes/hook/finder.php
+++ b/phpBB/includes/hook/finder.php
@@ -66,7 +66,7 @@ class phpbb_hook_finder
 		{
 			while (($file = readdir($dh)) !== false)
 			{
-				if (strpos($file, 'hook_') === 0 && substr($file, -(strlen($this->php_ext) + 1)) === '.' . $this->php_ext)
+				if (strpos($file, 'hook_') === 0 && substr($file, -strlen('.' . $this->php_ext)) === '.' . $this->php_ext)
 				{
 					$hook_files[] = substr($file, 0, -(strlen($this->php_ext) + 1));
 				}