The WP Page Permalink Extension plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.5.4. This is due to missing authorization checks on the `cwpp_trigger_flush_rewrite_rules` function hooked to `wp_ajax_cwpp_trigger_flush_rewrite_rules`. This makes it possible for authenticated attackers, with Subscriber-level access and above, to flush the site's rewrite rules via the `action` parameter.

The WP Page Permalink Extension plugin for WordPress is vulnerable to Missing Authorization in all versions up to, and including, 1.5.4. This is due to missing authorization checks on the `cwpp_trigger_flush_rewrite_rules` function hooked to `wp_ajax_cwpp_trigger_flush_rewrite_rules`. This makes it possible for authenticated attackers, with Subscriber-level access and above, to flush the site's rewrite rules via the `action` parameter.