Provide references for CVE-2013-4891.
Where can I find more information about CVE-2013-4891?
References are available at: https://nealpoole.com/blog/2013/07/codeigniter-21-xss-clean-filter-bypass/, https://github.com/bcit-ci/CodeIgniter/issues/4020, https://www.codeigniter.com/userguide2/changelog.html.