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.embed_images=T…
Published: 2026-04-21 · CVSS: 6.5 · CVSS 3.1
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.embed_images=True`, nbconvert's markdown renderer allows arbitrary file read via path traversal in image references. A malicious notebook can exfiltrate sensitive files from the conversion host by embedding them as base64 data URIs in the output HTML. nbconvert 7.17.1 contains a fix. As a workaround, do not enable `HTMLExporter.embed_images`; it is not enabled by default.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7