CodeIgniter4 is the 4.x branch of CodeIgniter, a PHP full-stack web framework. A cross-site scripting (XSS) vulnerability was found in `API\ResponseTrait` in Codeigniter4 prior to version 4.1.8. Attackers can do XSS attacks if a potential victim is using `API\ResponseTrait`. Version 4.1.8 contains a patch for this vulnerability. There are two potential workarounds available. Users may avoid using `API\ResponseTrait` or `ResourceController` Users may also disable Auto Route and use defined routes only.