The GNTT Post Title Ticker plugin for WordPress is vulnerable to Stored Cross-Site Scripting in version 1.0 via the `title-ticker-slide`, `title-ticker-fade`, and `title-ticker-typing` shortcodes. This is due to insufficient input sanitization and output escaping on shortcode attributes (notably `border`, `width`, `height`, `header_background`, `header_text_color`, and `id`) within the `gntt_title_ticker_slide()`, `gntt_title_ticker_fade()`, and `gntt_title_ticker_typing()` functions. None of these attribute values are passed through `esc_attr()` or any other escaping function before being concatenated into HTML output. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.