Jupyter nbconvert up to 7.17.0 path traversal

Summaryinfo

A vulnerability, which was classified as critical, has been found in Jupyter nbconvert up to 7.17.0. The impacted element is an unknown function. This manipulation causes path traversal. This vulnerability is tracked as CVE-2026-39378. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Jupyter nbconvert up to 7.17.0. It has been declared as critical. Affected by this vulnerability is an unknown functionality. The manipulation with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect confidentiality. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-39378 since 04/06/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. It demands that the victim is doing some kind of user interaction. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1006 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 309095 (Linux Distros Unpatched Vulnerability : CVE-2026-39378), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 7.17.1 eliminates this vulnerability. The upgrade is hosted for download at github.com.

The vulnerability is also documented in the databases at Tenable (309095) and EUVD (EUVD-2026-24025). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• Jupyter

Name

• nbconvert

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17.0

Website

• Product: https://github.com/jupyter/nbconvert/

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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