What’s Vulnerable › Vulnerabilities

CVE-2026-114140: nbconvert: File write via path traversal in cell output filenames

• Severity: high (CVSS 8.8 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-30
• Weakness: CWE-22

Description

The nbconvert tool, jupyter nbconvert, converts Jupyter notebooks to various other formats via Jinja templates. From 5.4.0 until 7.17.2, ExtractOutputPreprocessor in nbconvert/preprocessors/extractoutput.py joins the attacker-controlled cell output metadata filename to output_files_dir without limiting the result to the intended directory. When a victim converts a malicious notebook with the markdown, LaTeX, reStructuredText, or AsciiDoc exporter, path traversal in the output filename can write attacker-controlled output data to arbitrary locations accessible to the victim. Running the notebook cell again replaces the malicious output metadata, but merely converting the supplied notebook does not. This issue is fixed in version 7.17.2.

Affected products

• jupyter nbconvert: from 5.4.0, < 7.17.2

References

• https://github.com/jupyter/nbconvert/commit/ce4bd99aec31d81d759fa8eeb8643179392ec66f
• https://github.com/jupyter/nbconvert/releases/tag/v7.17.2
• https://github.com/jupyter/nbconvert/security/advisories/GHSA-pjvx-prjx-h659
• https://github.com/jupyter/nbconvert/security/advisories/GHSA-pjvx-prjx-h659

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