diff --git a/src/wp-includes/post.php b/src/wp-includes/post.php
index 5367f51e06f06..029ee636101a9 100644
--- a/src/wp-includes/post.php
+++ b/src/wp-includes/post.php
@@ -3295,7 +3295,7 @@ function wp_match_mime_types( $wildcard_mime_types, $real_mime_types ) {
 	foreach ( $patternses as $patterns ) {
 		foreach ( $patterns as $type => $pattern ) {
 			foreach ( (array) $real_mime_types as $real ) {
-				if ( preg_match( "#$pattern#", $real )
+				if ( is_string( $real ) && ! empty( $real ) && preg_match( "#$pattern#", $real )
 					&& ( empty( $matches[ $type ] ) || false === array_search( $real, $matches[ $type ], true ) )
 				) {
 					$matches[ $type ][] = $real;