docs: add changelog

Author: kenjis

CHANGELOG.md

@@ -7,6 +7,7 @@
 **SECURITY**
 
 * *Remote CLI Command Execution Vulnerability* was fixed. See the [Security advisory](https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-xjp4-6w75-qrj7) for more information.
+* *Cross-Site Request Forgery (CSRF) Protection Bypass Vulnerability* was fixed. See the [Security advisory](https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-4v37-24gm-h554) for more information.
 
 ## [v4.1.8](https://github.com/codeigniter4/CodeIgniter4/tree/v4.1.8) (2022-01-24)
 

user_guide_src/source/changelogs/v4.1.9.rst

@@ -12,4 +12,5 @@ Release Date: February xx, 2022
 SECURITY
 ********
 
-- *Remote CLI Command Execution Vulnerability* was fixed. See the `Security advisory <https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-xjp4-6w75-qrj7>`_ for more information.
+- *Remote CLI Command Execution Vulnerability* was fixed. See the `Security advisory GHSA-xjp4-6w75-qrj7 <https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-xjp4-6w75-qrj7>`_ for more information.
+- *Cross-Site Request Forgery (CSRF) Protection Bypass Vulnerability* was fixed. See the `Security advisory GHSA-4v37-24gm-h554 <https://github.com/codeigniter4/CodeIgniter4/security/advisories/GHSA-4v37-24gm-h554>`_ for more information.