diff --git a/wp-includes/class-walker-category.php b/wp-includes/class-walker-category.php
index 4c155c721b..6df6431b6b 100644
--- a/wp-includes/class-walker-category.php
+++ b/wp-includes/class-walker-category.php
@@ -146,7 +146,7 @@ class Walker_Category extends Walker {
 			if ( empty( $args['feed_image'] ) ) {
 				$link .= $name;
 			} else {
-				$link .= "<img src='" . $args['feed_image'] . "'$alt" . ' />';
+				$link .= "<img src='" . esc_url( $args['feed_image'] ) . "'$alt" . ' />';
 			}
 			$link .= '</a>';
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 3923de54e8..94638ed237 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44412';
+$wp_version = '5.1-alpha-44413';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.