Oveleon Cookie Bar is a cookie bar is for the Contao Open Source CMS and allows a visitor to define cookie & privacy settings for the website. Prior to versions 1.16.3 and 2.1.3, the `block/locale` endpoint does not properly sanitize the user-controlled `locale` input before including it in the backend's HTTP response, thereby causing reflected cross-site scripting. Versions 1.16.3 and 2.1.3 contain a patch for the vulnerability.