CVE-2026-48062 CodeIgniter: Uploaded file extension validation bypass in `ext_in` rule

CodeIgniter is a PHP full-stack web framework. Prior to 4.7.3, the extin upload validation rule in system/Validation/StrictRules/FileRules.php checked the MIME-derived guessed extension instead of the client-provided filename extension. As a result, an uploaded file named shell.php containing...