diff --git a/wp-includes/feed.php b/wp-includes/feed.php
index 4842c6e1a2..5e1d736d48 100644
--- a/wp-includes/feed.php
+++ b/wp-includes/feed.php
@@ -475,7 +475,7 @@ function rss_enclosure() {
 				 *
 				 * @param string $html_link_tag The HTML link tag with a URI and other attributes.
 				 */
-				echo apply_filters( 'rss_enclosure', '<enclosure url="' . trim( htmlspecialchars( $enclosure[0] ) ) . '" length="' . trim( $enclosure[1] ) . '" type="' . $type . '" />' . "\n" );
+				echo apply_filters( 'rss_enclosure', '<enclosure url="' . esc_url( trim( $enclosure[0] ) ) . '" length="' . absint( trim( $enclosure[1] ) ) . '" type="' . esc_attr( $type ) . '" />' . "\n" );
 			}
 		}
 	}
@@ -509,7 +509,7 @@ function atom_enclosure() {
 				 *
 				 * @param string $html_link_tag The HTML link tag with a URI and other attributes.
 				 */
-				echo apply_filters( 'atom_enclosure', '<link href="' . trim( htmlspecialchars( $enclosure[0] ) ) . '" rel="enclosure" length="' . trim( $enclosure[1] ) . '" type="' . trim( $enclosure[2] ) . '" />' . "\n" );
+				echo apply_filters( 'atom_enclosure', '<link href="' . esc_url( trim( $enclosure[0] ) ) . '" rel="enclosure" length="' . absint( trim( $enclosure[1] ) ) . '" type="' . esc_attr( trim( $enclosure[2] ) ) . '" />' . "\n" );
 			}
 		}
 	}