GHSA-mmj4-63m4-r6h5

CodeIgniter: Uploaded file extension validation bypass in `is_image` and `mime_in` rules

### Impact This is an unsafe file upload validation vulnerability that can lead to remote code execution in vulnerable application configurations. Applications are impacted when they: - validate uploads using `is_image` or `mime_in` without an independent safe extension check, such as `ext_in` on patched versions - save uploaded files using the client-supplied filename - place uploads in a web-accessible directory where PHP files can execute ### Patches Upgrade to v4.7.4 or later. ### Workarounds - Save uploads outside the public web root, preferably under `writable/uploads`. - Use `$file->store()` or `$file->move($path, $file->getRandomName())` instead of preserving the original client filename. - Disable script execution in any public upload directory. - Manually verify the client filename extension before moving the file. - For image uploads, reject files when `$file->getClientExtension()` is not an allowed image extension. - For exact MIME-type validation, reject files when `$file->getClientExtension()` does not match `$file->guessExtension()`.