CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.5.0, ci4ms Backup::restore extracts user uploaded ZIP archives without validating entry names, allowing an authenticated backend user with the backup create permission to write files to arbitrary filesystem locations (Zip Slip) and achieve remote code execution by dropping a PHP file under the public web root. This issue has been patched in version 0.31.5.0.

Affected: Packagist: ci4-cms-erp/ci4ms

### Summary ci4ms Backup::restore extracts user uploaded ZIP archives without validating entry names, allowing an authenticated backend user with the backup create permission to write files to arbitrary filesystem locations (Zip Slip) and achieve remote code execution by dropping a PHP file under the public web root.

### Details modules/Backup/Controllers/Backup.php:80-119 implements the restore action. The uploaded file is moved to `WRITEPATH . 'uploads/'`, and if the extension is `zip`, ZipArchive::extractTo() is called directly without iterating entries to verify they resolve inside the destination:

```php public function restore() { $valData = ([ 'backup_file' => ['label' => 'Backup File', 'rules' => 'uploaded[backup_file]|ext_in[backup_file,zip]'], ]); if ($this->validate($valData) == false) return redirect()->route('backup')->withInput()->with('errors', $this->validator->getErrors()); $file = $this->request->getFile('backup_file');

if ($file && $file->isValid() && ! $file->hasMoved()) { $newName = $file->getRandomName(); $uploadPath = WRITEPATH . 'uploads/'; ... $filePath = WRITEPATH . 'uploads/' . $newName; $sqlPath = $filePath; if ($ext === 'zip') { $zip = new \ZipArchive(); if ($zip->open($filePath) === true) { $zip->extractTo($uploadPath); // no entry-name validation $sqlPath = $uploadPath . $zip->getNameIndex(0);…