diff -Nuar a/vendor/magento/framework/Filesystem/Directory/DenyListPathValidator.php b/vendor/magento/framework/Filesystem/Directory/DenyListPathValidator.php
--- a/vendor/magento/framework/Filesystem/Directory/DenyListPathValidator.php	(revision d40e8cbfd24ac841900166877e9910f9d549fdf5)
+++ b/vendor/magento/framework/Filesystem/Directory/DenyListPathValidator.php	(revision 7d6a3eeb669d4a11978bf639dc2536ef23d56d09)
@@ -71,7 +71,7 @@
 
         foreach ($this->fileDenyList as $file) {
             $baseName = pathinfo($actualPath, PATHINFO_BASENAME);
-            if (str_contains($baseName, $file) || preg_match('#' . "\." . $file . '#', $fullPath)) {
+            if (strpos($baseName, $file) !== false || preg_match('#' . "\." . $file . '#', $fullPath)) {
                 throw new ValidatorException(
                     new Phrase('"%1" is not a valid file path', [$path])
                 );