How severe is CVE-2026-114140?

No CVSS score has been assigned to CVE-2026-114140 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-114140?

CVE-2026-114140 affects the following packages: nbconvert (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-114140?

Update nbconvert to 7.17.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-114140 is resolved across your whole dependency graph.

How do I detect CVE-2026-114140 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbconvert, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-114140 if there is no patch (or I can't update yet)?

Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Is CVE-2026-114140 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-114140 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-114140?

CVE-2026-114140 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 23th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-114140?

CVE-2026-114140 is classified as Path Traversal (CWE-22). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-114140 published, and has it been updated?

CVE-2026-114140 was published on October 21, 2026 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

CVE-2026-114140 — nbconvert

Fix: jupyter/nbconvert@ce4bd99

CVE-2026-114140 is a Path Traversal vulnerability in nbconvert. A fix is available for nbconvert — see the affected versions and patch details below.

nbconvert: File write via path traversal in cell output filenames

Also known asGHSA-pjvx-prjx-h659

Published

Oct 21, 2026

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs23th percentile — riskier than 23% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍nbconvert

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Summary

nbconvert <= v7.17.1 has an arbitrary file write vulnerability due to a path traversal in ipynb cell output metadata, more specifically on the filename attribute.

Vulnerable converters : --to markdown, --to latex, --to rst, --to asciidoc.

In ExtractOutputPreprocessor, extractoutput.py:116-119 joins attacker-controlled path to output_files_dir with no canonicalization check, enabling arbitrary file write.

This is a sibling vulnerability of https://github.com/advisories/GHSA-4c99-qj7h-p3vg.

Impact

If a victim runs nbconvert on a malicious ipynb file, it can create some files with arbitrary data in arbitrary locations, i.e. override authorized_keys.

Note that running the cell with jupyter overrides the output, so it would "clean up" malicious cells.

PoC

In a ipynb file:


"cells": [{
        "cell_type": "code", "id": "abc123", "execution_count": 1,
        "metadata": {}, "source": "# PoC",
        "outputs": [{
            "output_type": "display_data",
            "metadata": {
                "filename": "../../../tmp/PWNED.png"  # ← traverses outside output_dir
            },
            "data": {
                # minimal valid PNG (1×1 pixel)
                "image/png": "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg=="
            }
        }]
    }]

Patches

Fixed in

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`nbconvert`	≥ 5.4.0&&< 7.17.2	7.17.2`pip install --upgrade 'nbconvert==7.17.2'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbconvert, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nbconvert to 7.17.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-114140 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.

Frequently Asked Questions

### Summary nbconvert <= v7.17.1 has an arbitrary file write vulnerability due to a path traversal in ipynb cell output metadata, more specifically on the filename attribute. Vulnerable converters : `--to markdown`, `--to latex`, `--to rst`, `--to asciidoc`. In `ExtractOutputPreprocessor`, `extractoutput.py:116-119` joins attacker-controlled `path` to `output_files_dir` with no canonicalization check, enabling arbitrary file write. This is a sibling vulnerability of https://github.com/advisories/GHSA-4c99-qj7h-p3vg. ### Impact If a victim runs nbconvert on a malicious ipynb file, it can

O3 Security · Impact-Aware SCA

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