GHSA-qvfw-j98x-7q72

multer vulnerable to file size limit bypass via async fileFilter race condition

### Impact When `multer` is configured with an asynchronous `fileFilter`, the `limits.fileSize` limit can be bypassed. The `'limit'` event is registered inside the async `fileFilter` callback, so if a file exceeds `limits.fileSize` before that callback runs, the event is missed and the oversized upload is accepted instead of being rejected with a `LIMIT_FILE_SIZE` error. Applications that rely on `limits.fileSize` to reject oversized uploads are affected on all upload methods (`.single()`, `.array()`, `.fields()`, `.any()`). Uploads using a synchronous `fileFilter` are not affected. ### Patches Users should upgrade to `2.3.0`. ### Workarounds Use a synchronous `fileFilter`, or validate the uploaded file size after the upload completes.