Ticket #39552: 39552.1.patch

wp-includes/functions.php

@@ -2377 +2377 @@
                 $mime = false;
         }
 
+        try {
+                if ( false === $mime && function_exists( 'finfo_file' ) ) {
+                        // Use finfo_file if available to validate non-image files.
+                        $finfo = finfo_open( FILEINFO_MIME_TYPE );
+                        $mime = finfo_file( $finfo, $file );
+                        finfo_close( $finfo );
+                }
+        } catch ( Exception $e ) {
+                $mime = false;
+        }
+
         return $mime;
 }