Skip to content
Noroxi
CVE-2026-40171· NVD / CVE Program· CNA GitHub_M

Jupyter Notebook and JupyterLab token theft via stored XSS in help command linker

Noroxi assessment

Priority: Monitor (action score 33/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.66% (FIRST EPSS); higher than 51.1% of all records.
  • Anyone who can reach it over the internet can trigger it. Administrator privileges are required. No special conditions are required; it is repeatable.
  • Fixed version: jupyter-notebook (Debian:14) 7.4.7-3; jupyterlab (Debian:14) 4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3; @jupyter-notebook/help-extension (npm) 7.5.6.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to jupyter-notebook (Debian:14) 7.4.7-3; jupyterlab (Debian:14) 4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3; @jupyter-notebook/help-extension (npm) 7.5.6 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

In Jupyter Notebook versions 7.0.0 through 7.5.5, JupyterLab versions 4.5.6 and earlier, and the corresponding @jupyter-notebook/help-extension and @jupyterlab/help-extension packages before 7.5.6 and 4.5.7, a stored cross-site scripting issue in the help command linker can be chained with attacker-controlled notebook content to steal authentication tokens with a single click. An attacker can craft a malicious notebook file containing elements that appear indistinguishable from legitimate controls and trigger execution when a user interacts with them. Successful exploitation allows theft of the user's authentication token and complete takeover of the Jupyter session through the REST API, including reading files, creating or modifying files, accessing kernels to execute arbitrary code, and creating terminals for shell access. This issue has been fixed in Notebook 7.5.6, JupyterLab 4.5.7, @jupyter-notebook/help-extension 7.5.6, and @jupyterlab/help-extension 4.5.7. As a workaround, disable the affected help extensions or set allowCommandLinker to false in the sanitizer configuration.

HighCVSS 8.4 · v4.0—No exploit Fix available
Published
May 6, 2026
Updated
Jun 17, 2026
EPSS
0.6% · 51th percentile

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.6%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
8.4
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

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
  • No public exploit code on record
  • A fix has been released

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

Follow CVE-2026-40171

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

One daily email digest (06:00 UTC); connect a webhook for KEV listings and weaponized exploits instantly.

Your free account also gets you

Running WordPress? Scan your site free with WP Lens

  • Stack alerts: add the products and versions you run, get the new CVEs that affect them
  • Uptime monitoring: 1 site, instant email when it goes down
  • Add your domain: subdomains and takeover risk scanned every week (1 domain)
  • 10 scans an hour on the security tools (3 a day without an account), an API key and MCP
  • All your scans in one panel: findings, what changed in the last scan, a report per domain or per client (PDF, share link)
All free tools

Sign up with email · Have an account? Sign in

Free account, no card. Unfollow any time.

Don't want an account? Get "Exploited this week" by email every MondayDon't want an account? RSS feed for jupyter records

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

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.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

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 notebook

    • >=7.0.0, <= 7.5.5affected

  • jupyter-notebook help-extension

    • >=7.0.0,<= 7.5.5affected

  • jupyterlab help-extension

    • <=4.5.6affected

  • jupyterlab jupyterlab

    • <= 4.5.6affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:13jupyterlabfrom 0—
Debian:14jupyter-notebookbefore 7.4.7-37.4.7-3
Debian:14jupyterlabbefore 4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-34.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3
npm@jupyter-notebook/help-extensionfrom 7.0.0 · before 7.5.67.5.6
npm@jupyterlab/help-extensionbefore 4.5.74.5.7
openSUSE:Tumbleweedpython-jupyterlabbefore 4.5.7-1.14.5.7-1.1
openSUSE:Tumbleweedpython-notebookbefore 7.5.6-1.17.5.6-1.1
PyPIjupyterlabbefore 4.5.74.5.7
PyPInotebookfrom 7.0.0 · before 7.5.67.5.6

Same product

jupyter: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-32798Failure to Sanitize Special Elements into a Different Plane (Special Element Injection) in notebook
    39Monitor
  • CVE-2018-8768In Jupyter Notebook before 5.4.1, a maliciously forged notebook file can bypass sanitization to execute JavaScript in the notebook context.
    31Monitor
  • CVE-2022-24758Insertion of Sensitive Information into Log File affects Jupyter Notebook
    30Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2018-21030Oct 31, 2019 · Jupyter Notebook before 5.5.0 does not use a CSP header to treat served files as belonging to a separate origin.
    21Monitor
  • ← EarlierCVE-2020-26215Nov 18, 2020 · Open redirect in Jupyter Notebook
    24Monitor
  • ← EarlierCVE-2022-29238Jun 14, 2022 · Forced Browsing in Jupyter Notebook
    17Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
debian:jupyter-notebook7.4.7-3 · Debian:14Package registry (OSV)
debian:jupyterlab4.4.10+ds1+~3.1.0+~0.16.6+~cs1.4.4-3 · Debian:14Package registry (OSV)
npm:@jupyter-notebook/help-extension7.5.6Package registry (OSV)
npm:@jupyterlab/help-extension4.5.7Package registry (OSV)
opensuse:python-jupyterlab4.5.7-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:python-notebook7.5.6-1.1 · openSUSE:TumbleweedPackage registry (OSV)
PyPI:jupyterlab4.5.7Package registry (OSV)
PyPI:notebook7.5.6Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

No dated events beyond publication.

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.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

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

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • Administrator privileges are required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
High
User interaction
A
Scope
X

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

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

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

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

References

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

All records