CVE-2026-39377

Name	CVE-2026-39377
Description	The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. Versions 6.5 through 7.17.0 allow 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. Version 7.17.1 contains a patch.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
nbconvert (PTS)	bullseye	5.6.1-3	vulnerable
	bullseye (security)	5.6.1-3+deb11u1	vulnerable
	bookworm	6.5.3-3	vulnerable
	trixie	7.16.6-1	vulnerable
	forky, sid	7.17.0-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
nbconvert	source	(unstable)	(unfixed)

https://github.com/jupyter/nbconvert/security/advisories/GHSA-4c99-qj7h-p3vg