diff --git a/src/wp-includes/functions.php b/src/wp-includes/functions.php
index fcb60e6eb3846..0704d067a028c 100644
--- a/src/wp-includes/functions.php
+++ b/src/wp-includes/functions.php
@@ -2192,7 +2192,7 @@ function wp_normalize_path( $path ) {
 	}
 
 	// Standardize all paths to use '/'.
-	$path = str_replace( '\\', '/', $path );
+	$path = str_replace('\\', '/', $path ?? '');
 
 	// Replace multiple slashes down to a singular, allowing for network shares having two slashes.
 	$path = preg_replace( '|(?<=.)/+|', '/', $path );
@@ -7357,7 +7357,7 @@ function _device_can_upload() {
  * @return bool True if the path is a stream URL.
  */
 function wp_is_stream( $path ) {
-	$scheme_separator = strpos( $path, '://' );
+	$scheme_separator = strpos($path ?? '', '://');
 
 	if ( false === $scheme_separator ) {
 		// $path isn't a stream.