CVE-2026-39378 nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding

The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. In versions 6.5 through 7.17.0, when HTMLExporter.embedimages=True, nbconvert's markdown renderer allows arbitrary file read via path traversal in image references. A malicious notebook...