1、创建中间件

php artisan make:middleware XSSClean

2、编辑app/Http/Middleware/XSSClean.php文件

query->all();
        $req = $request->request->all();
        // $all = $request->all();

        array_walk_recursive($query, function (&$params) {
            // $params = htmlspecialchars($params);
            $params = strip_tags($params);
        });

        $request->query->replace($query);
        // $request->merge($query);

        array_walk_recursive($req, function (&$params) {
            // $params = htmlspecialchars($params);
            $params = strip_tags($params);
        });
        $request->request->replace($req);
        // $request->merge($req);

        return $next($request);
    }
}

3、配置app/Http/Kernel.php文件

    protected $middleware = [
        // ...
        XSSClean::class, // 增加xss处理中间件
        // ...
    ];

其他方案：

composer require mews/purifier

参考：

laravel8 实现XSS预防处理方案_laravel防止转义xss-CSDN博客

360通用php防护代码(使用操作详解)_php编程-跟版网

http://www.cnblogs.com/bingtang123/p/12844659.html