diff --git src/wp-includes/pluggable.php src/wp-includes/pluggable.php
index 9936858..e9f66d6 100644
--- src/wp-includes/pluggable.php
+++ src/wp-includes/pluggable.php
@@ -976,6 +976,9 @@ if ( ! function_exists( 'wp_clear_auth_cookie' ) ) :
 		setcookie( PASS_COOKIE, ' ', time() - YEAR_IN_SECONDS, COOKIEPATH, COOKIE_DOMAIN );
 		setcookie( USER_COOKIE, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH, COOKIE_DOMAIN );
 		setcookie( PASS_COOKIE, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH, COOKIE_DOMAIN );
+
+		// Post password cookie
+		setcookie( 'wp-postpass_' . COOKIEHASH, ' ', time() - YEAR_IN_SECONDS, SITECOOKIEPATH, COOKIE_DOMAIN );
 	}
 endif;