Vulnerability Description
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.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Jupyter | Nbconvert | >= 6.5.0, < 7.17.1 |
Related Weaknesses (CWE)
References
- https://github.com/jupyter/nbconvert/releases/tag/v7.17.1Product
- https://github.com/jupyter/nbconvert/security/advisories/GHSA-7jqv-fw35-gmx9MitigationVendor Advisory
FAQ
What is CVE-2026-39378?
CVE-2026-39378 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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 markd...
How severe is CVE-2026-39378?
CVE-2026-39378 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-39378?
Check the references section above for vendor advisories and patch information. Affected products include: Jupyter Nbconvert.