A reflected XSS vulnerability was found in includes/admin/table-printer.php in the broken-link-checker (aka Broken Link Checker) plugin 1.11.8 for WordPress. This allows unauthorized users to inject client-side JavaScript into an admin-only WordPress page via the wp-admin/tools.php?page=view-broken-links s_filter parameter in a search action.
https://wpvulndb.com/vulnerabilities/9917
https://wordpress.org/plugins/broken-link-checker/#developers