nbconvert: File write via path traversal in cell output filenames
Affects nbconvert 5.4.0 through 7.17.1 when converting notebooks to markdown, LaTeX, reStructuredText or AsciiDoc. CVSS rates it High (8.8). Fixed in 7.17.2.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 7.17.2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: poc
- Automatable: no
- Technical impact: total
Summary
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.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: poc · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- jupyter nbconvert
From 5.4.0 · fixed in 7.17.2
- nbconvertPyPI
From 5.4.0 · fixed in 7.17.2
References 3
GitHub · jupyter/nbconvert
Questions about CVE-2026-114140
What does this mean?
A path traversal flaw in cell output filenames lets nbconvert write files with attacker-supplied data to arbitrary locations. The advisory gives overwriting authorized_keys as an example.Source: github.com
Am I affected, and how do I check?
Versions 5.4.0 through 7.17.1 are affected, but only when converting notebooks with the markdown, LaTeX, reStructuredText or AsciiDoc exporter (--to markdown, --to latex, --to rst or --to asciidoc). To check the installed version, run jupyter nbconvert --version.Source: github.com
What should I do about it?
Upgrade nbconvert to 7.17.2 or later, which contains the fix.Source: github.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. CISA's SSVC assessment notes a proof of concept exists. No public exploit code is tracked.Source: cve.now feed data