Jupyter Nbconvert Path Traversal Vulnerability Allowing Arbitrary File Writes

A vulnerability in Jupyter Nbconvert versions 6.5 prior to 7.17.1 allows arbitrary file writes to locations outside the intended output directory. This issue arises when the nbconvert tool processes notebooks with crafted cell attachment filenames. The ExtractAttachmentsPreprocessor directly passes these filenames to the filesystem without proper sanitization, enabling path traversal attacks. As a result, an attacker can manipulate the destination path, filename, file extension, and file content of the written files.

Impact

Exploitation of this vulnerability could lead to unauthorized file writes with arbitrary content, potentially overwriting existing files or creating new ones in sensitive locations, depending on the permissions of the process running Nbconvert.

Remediation

Users can upgrade to Jupyter Nbconvert version 7.17.1, which includes a patch for this vulnerability. Alternatively, the ExtractAttachmentsPreprocessor can be disabled by setting 'c.ExtractAttachmentsPreprocessor.enabled = False'.