diff --git src/wp-includes/media.php src/wp-includes/media.php
index 6b0187a..8a5b548 100644
--- src/wp-includes/media.php
+++ src/wp-includes/media.php
@@ -1060,6 +1060,11 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
 	 */
 	foreach ( $image_sizes as $image ) {
 
+		// Check if image meta isn't corrupted.
+		if ( ! is_array( $image ) || 1 > strpos( $image['file'], '.' ) ) {
+			continue;
+		}
+
 		// If the file name is part of the `src`, we've confirmed a match.
 		if ( ! $src_matched && false !== strpos( $image_src, $dirname . $image['file'] ) ) {
 			$src_matched = true;