CVE.org (no NVD analysis yet)· CNA GitHub_M

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

HighCVSS 8.8 · v4.0—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 35/100)

Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
Probability of exploitation in the next 30 days: 0.45% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No special conditions are required; it is repeatable.
Fixed version: jupyter nbconvert 7.17.2.

Low priority for now. Upgrade to jupyter nbconvert 7.17.2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Path traversal

Published: Oct 21, 2026
Updated: Oct 30, 2026
EPSS: 0.4% · 39th percentile
CWE: CWE-22

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 35 / 40 · 8.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: proof of concept
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 8.8; NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
Proof of concept exists, no weaponized module
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

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—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

jupyter nbconvert
- >= 5.4.0, < 7.17.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	nbconvert	from 0	—
Debian:14	nbconvert	before 7.17.2-1	7.17.2-1
PyPI	nbconvert	from 5.4.0 · before 7.17.2	7.17.2

Same product

jupyter: all records

Other highest-scoring records for the same primary product.

CVE-2025-53000nbconvert has an uncontrolled search path that leads to unauthorized code execution on Windows
34Monitor
CVE-2026-39378nbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding
26Monitor
CVE-2026-39377nbconvert has an Arbitrary File Write via Path Traversal in Cell Attachment Filenames
26Monitor

Published before and after this one in the same product

← EarlierCVE-2021-32862Aug 18, 2022 · nbconvert vulnerable to cross-site scripting (XSS) via multiple exploit paths
21Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
jupyter nbconvert	7.17.2 · description	Vendor (CNA)
debian:nbconvert	7.17.2-1 · Debian:14	Package registry (OSV)
PyPI:nbconvert	7.17.2	Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
Source	Kind	Date
Proof-of-concept repository on GitHub	stars:0	2026-11-09

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

PublishedOct 21, 2026
Fix recordedOct 21, 2026same day
First PoCNov 9, 2026+18 d
TodayNov 13, 2026+23 d

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

jupyter/nbconvertcommit ce4bd99

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

CVE-2026-39377183 days apartnbconvert has an Arbitrary File Write via Path Traversal in Cell Attachment Filenames
26Monitor
CVE-2026-39378183 days apartnbconvert has an Arbitrary File Read via Path Traversal in HTMLExporter Image Embedding
26Monitor

Not on record for this CVE: researcher credit · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: A
Scope: X

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1const file = path.join(ROOT, req.query.name);
2res.sendFile(file);

Fixed

1const file = path.resolve(ROOT, req.query.name);
2if (!file.startsWith(ROOT + path.sep)) {
3  return res.sendStatus(400);
4}
5res.sendFile(file);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Exploit maturitynone → pocNov 10, 2026, 3:36 AM UTC
SSVC exploitation— → pocOct 30, 2026, 4:07 PM UTC
Exploit maturity— → noneOct 21, 2026, 10:09 PM UTC
Fix✗ → ✓Oct 21, 2026, 10:09 PM UTC

For records you follow, these changes also arrive as notifications. →

References

github.com/jupyter/nbconvert/commit/ce4bd99aec31d81d759fa8eeb8643179392ec66f

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records

Noroxi analysis

What does it mean in your environment?

We use this product, ask for help

Data sources and verification

CNA: GitHub_M

CVE.org (CNA)Oct 30, 2026, 3:01 PM UTC
CISA ADPOct 30, 2026, 3:01 PM UTC
NVDOct 30, 2026, 3:16 PM UTC
FIRST EPSSNov 12, 2026, 12:00 AM UTC
OSV / GHSANov 13, 2026, 3:18 AM UTC
PoC-in-GitHubNov 13, 2026, 3:18 AM UTC

Each line is when that source was last processed for this record.