CodeIgniter4 has a validation bypass when uploading file extensions via `ext_in` rule

Impact The extin upload validation rule checked the MIME-derived guessed extension instead of the client-provided filename extension. As a result, an uploaded file named shell.php containing GIF-like content could pass validation such as:...

PT-2026-48810

Name of the Vulnerable Software and Affected Versions CodeIgniter versions prior to 4.7.3 Description An upload validation bypass exists in the ext in rule within system/Validation/StrictRules/FileRules.php. The rule incorrectly validates the MIME-derived guessed extension instead of the actual...