CodeIgniter is an open source PHP full-stack web framework. Deserialization of Untrusted Data was found in the `old()` function in CodeIgniter4. Remote attackers may inject auto-loadable arbitrary objects with this vulnerability, and possibly execute existing PHP code on the server. We are aware of a working exploit, which can lead to SQL injection. Users are advised to upgrade to v4.1.6 or later. Users unable to upgrade as advised to not use the `old()` function and form_helper nor `RedirectResponse::withInput()` and `redirect()->withInput()`.

Affected: Packagist: codeigniter4/framework

### Impact Deserialization of Untrusted Data was found in the `old()` function in CodeIgniter4. Remote attackers may inject auto-loadable arbitrary objects with this vulnerability, and possibly execute existing PHP code on the server. We are aware of a working exploit, which can lead to SQL injection.

### Patches Upgrade to v4.1.6 or later.

### Workarounds Do not use: - `old()` and form_helper - `RedirectResponse::withInput()` and `redirect()->withInput()`

### References - [PHP Object Injection | OWASP](https://owasp.org/www-community/vulnerabilities/PHP_Object_Injection)

### For more information If you have any questions or comments about this advisory: * Open an issue in [codeigniter4/CodeIgniter4](https://github.com/codeigniter4/CodeIgniter4/issues) * Email us at [SECURITY.md](https://github.com/codeigniter4/CodeIgniter4/blob/develop/SECURITY.md)