Cloudanix VulnDB

CVE-2026-114140

None

CVSS

—

EPSS

0.4%

Published

Oct 21, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A notebook conversion tool can be tricked into placing files in the wrong locations on a computer when it processes a specially made notebook file.

Exploitation
Requires User Interaction
Attacker needs
User Interaction
Complexity
Low
Impact
Data Tampering
Component
Library
Class
Path Traversal
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Path traversal in ExtractOutputPreprocessor joins attacker-controlled output metadata filenames directly to output_files_dir without directory restriction, allowing writes outside the intended path during notebook conversion with markdown, LaTeX, reStructuredText, or AsciiDoc exporters.

Why it matters to the business

Attackers can overwrite arbitrary files accessible to the converting user, enabling tampering with configuration, scripts, or data that may lead to further compromise or operational disruption; the flaw's recent disclosure and lack of known exploitation mean organizations have a short window to act before potential abuse increases.

How an attack unfolds

An attacker embeds a path-traversal sequence in the filename field of cell output metadata within a Jupyter notebook; when a victim runs nbconvert with an affected exporter the malicious filename is concatenated without sanitization, resulting in attacker-controlled content being written to an arbitrary filesystem location.

How to fix it

Upgrade nbconvert to version 7.17.2 or later; avoid converting untrusted notebooks with older versions until patched.

How to confirm the fix worked

Verify installed nbconvert version is at least 7.17.2; test conversion of a notebook containing a traversal filename and confirm output remains confined to the expected directory.

Typical attack path

  1. Create a Jupyter notebook containing malicious cell output metadata with a path traversal filename
  2. Distribute the notebook to a target user or environment that performs conversion
  3. Victim executes nbconvert using markdown, LaTeX, reStructuredText, or AsciiDoc exporter on the supplied notebook
  4. Arbitrary file write occurs on the victim's accessible filesystem

How to detect it

Monitor for nbconvert processes writing files outside expected output directories; inspect conversion logs for filenames containing path traversal sequences such as ../ or ..\.

What your security team should do

  • Immediately upgrade all nbconvert installations to 7.17.2 or newer
  • Scan package manifests and environments for versions between 5.4.0 and 7.17.1
  • Restrict conversion of notebooks from untrusted sources until remediation is complete

The record

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 packages

Ecosystem Package Introduced Fixed

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