GHSA-4c99-qj7h-p3vg nbconvert has an Arbitrary File Write via Path Traversal in Cell Attachment Filenames

• PyPI nbconvert: >= 6.5.0, < 7.17.1 → fixed in 7.17.1

Arbitrary File Write via Path Traversal in Cell Attachment Filenames Summary nbconvert allows arbitrary file writes to locations outside the intended output directory when processing notebooks containing crafted cell attachment filenames. The `ExtractAttachmentsPreprocessor` passes attachment filenames directly to the filesystem without sanitization, enabling path traversal attacks. This vulnerability provides complete control over both the destination path and file extension. Impact This vulnerability allows writing files with arbitrary content to arbitrary filesystem locations, limited only by the permissions of the process running nbconvert. The attacker controls: • Full destination path (via `../` traversal) • Filename • File extension • File content Patches • upgrade to nbconvert v7.17.1 Workarounds disable ExtractAttachmentsPreprocessor by setting: ```python c. ExtractAttachmentsPreprocessor.enabled = False ```