Zen Cart 1.5.6d allows reflected XSS via the main_page parameter to includes/templates/template_default/common/tpl_main_page.php or includes/templates/responsive_classic/common/tpl_main_page.php.
{
    "github_reviewed_at": "2023-07-06T20:25:05Z",
    "severity": "MODERATE",
    "github_reviewed": true,
    "cwe_ids": [
        "CWE-79"
    ],
    "nvd_published_at": "2021-03-19T04:15:00Z"
}