ApostropheCMS is an open-source Node.js content management system. Prior to 4.33.0 of ApostropheCMS and 3.7.0 of the import-export module, import routes invoke bigUploadMiddleware without an early authorize callback, allowing unauthenticated requests to perform upload initialization, chunk storage, temporary processing, and attacker-declared cleanup work before the later user check rejects the import. This issue is fixed in ApostropheCMS 4.33.0 and import-export 3.7.0.