Vulnerability · Published Oct 21, 2026 · Assigned by GitHub_M
CVE-2026-114140nbconvert: File write via path traversal in cell output filenames
High 8.8
In plain English
A high-severity path traversal in nbconvert from jupyter. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nbconvert | no fix listed | DEBIAN-CVE-2026-114140 |
| Debian:13 | nbconvert | no fix listed | DEBIAN-CVE-2026-114140 |
| Debian:14 | nbconvert | no fix listed | DEBIAN-CVE-2026-114140 |
| PyPI | nbconvert | 7.17.2 | GHSA-pjvx-prjx-h659 |
| Ubuntu:22.04:LTS | nbconvert | no fix listed | UBUNTU-CVE-2026-114140 |
| Ubuntu:24.04:LTS | nbconvert | no fix listed | UBUNTU-CVE-2026-114140 |
| Ubuntu:26.04:LTS | nbconvert | no fix listed | UBUNTU-CVE-2026-114140 |
| Ubuntu:26.10 | nbconvert | no fix listed | UBUNTU-CVE-2026-114140 |
Affected products (as reported)
Weakness: CWE-22 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H