diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index 1590899ce5..637a13381e 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -2730,19 +2730,19 @@ function wp_rel_nofollow( $text ) {
  */
 function wp_rel_nofollow_callback( $matches ) {
 	$text = $matches[1];
-	$atts = shortcode_parse_atts( $matches[1] );
+	$atts = wp_kses_hair( $matches[1], wp_allowed_protocols() );
 	$rel  = 'nofollow';
 
 	if ( ! empty( $atts['href'] ) ) {
-		if ( in_array( strtolower( wp_parse_url( $atts['href'], PHP_URL_SCHEME ) ), array( 'http', 'https' ), true ) ) {
-			if ( strtolower( wp_parse_url( $atts['href'], PHP_URL_HOST ) ) === strtolower( wp_parse_url( home_url(), PHP_URL_HOST ) ) ) {
+		if ( in_array( strtolower( wp_parse_url( $atts['href']['value'], PHP_URL_SCHEME ) ), array( 'http', 'https' ), true ) ) {
+			if ( strtolower( wp_parse_url( $atts['href']['value'], PHP_URL_HOST ) ) === strtolower( wp_parse_url( home_url(), PHP_URL_HOST ) ) ) {
 				return "<a $text>";
 			}
 		}
 	}
 
 	if ( ! empty( $atts['rel'] ) ) {
-		$parts = array_map( 'trim', explode( ' ', $atts['rel'] ) );
+		$parts = array_map( 'trim', explode( ' ', $atts['rel']['value'] ) );
 		if ( false === array_search( 'nofollow', $parts ) ) {
 			$parts[] = 'nofollow';
 		}
@@ -2751,7 +2751,11 @@ function wp_rel_nofollow_callback( $matches ) {
 
 		$html = '';
 		foreach ( $atts as $name => $value ) {
-			$html .= "{$name}=\"" . esc_attr( $value ) . "\" ";
+			if ( isset( $value['vless'] ) && 'y' === $value['vless'] ) {
+				$html .= $name . ' ';
+			} else {
+				$html .= "{$name}=\"" . esc_attr( $value['value'] ) . '" ';
+			}
 		}
 		$text = trim( $html );
 	}
diff --git a/tests/phpunit/tests/formatting/WPRelNoFollow.php b/tests/phpunit/tests/formatting/WPRelNoFollow.php
index bd13a83b5e..9dbea786df 100644
--- a/tests/phpunit/tests/formatting/WPRelNoFollow.php
+++ b/tests/phpunit/tests/formatting/WPRelNoFollow.php
@@ -74,4 +74,10 @@ class Tests_Rel_No_Follow extends WP_UnitTestCase {
 			),
 		);
 	}
+
+	public function test_append_no_follow_with_valueless_attribute() {
+		$content = '<p>This is some cool <a href="demo.com" download rel="hola">Code</a></p>';
+		$expected = '<p>This is some cool <a href=\"demo.com\" download rel=\"hola nofollow\">Code</a></p>';
+		$this->assertEquals( $expected, wp_rel_nofollow( $content ) );
+	}
 }