Media Library Assistant · cross-site scripting

The Media Library Assistant plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the bulk edit preset export/import mechanism in versions up to and including 3.35. This is due to insufficient output escaping on preset field values when they are rendered in HTML attribute contexts in the mla_generate_bulk_edit_form_fieldsets() function and mla-bulk-edit-fieldsets.tpl template. While wp_kses() filtering is applied during preset export for users without unfiltered_html capability, this does not prevent attribute injection attacks since the malicious payload consists of quotes and HTML attributes rather than HTML tags. When preset values are retrieved and rendered, they are directly assigned to template variables without esc_attr() escaping and then inserted into input element value attributes via simple string replacement. This makes it possible for authenticated attackers, with Author-level access and above (upload_files capability), to inject arbitrary web scripts that execute when an administrator imports the poisoned preset and the targeted input field receives focus.