GHSA-RCH3-82JR-F9W9
Vulnerability from github – Published: 2026-04-30 17:25 – Updated: 2026-05-08 19:26
VLAI
Summary
Jupyter Notebook Vulnerable to Authentication Token Theft via CommandLinker XSS
Details
Impact
A stored Cross-Site Scripting (XSS) vulnerability in Jupyter Notebook allows attackers to steal authentication tokens from users who open malicious notebook files and interact with elements that the attacker can make look indistinguishable from legitimate controls (single click interaction).
The vulnerability enables complete account takeover through the Jupyter REST API, allowing the attacker to: 1. Read all files 2. Modify/create files 3. Access running kernels and execute arbitrary code 4. Create terminals for shell access
Patches
Jupyter Notebook 7.5.6 and JupyterLab 4.5.7 include patches for this vulnerability.
Workarounds
The help extension can be disabled via CLI:
jupyter labextension disable @jupyter-notebook/help-extension
jupyter labextension disable @jupyterlab/help-extension
Hardening
The patched versions include a toggle to disable the command linker functionality altogether, for example via overrides.json:
{
"@jupyterlab/apputils-extension:sanitizer": {
"allowCommandLinker": false
}
}
Resources
- https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files
Acknowledgments
Reported by Daniel Teixeira - NVIDIA AI Red Team
Severity
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 7.5.5"
},
"package": {
"ecosystem": "npm",
"name": "@jupyter-notebook/help-extension"
},
"ranges": [
{
"events": [
{
"introduced": "7.0.0"
},
{
"fixed": "7.5.6"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 7.5.5"
},
"package": {
"ecosystem": "PyPI",
"name": "notebook"
},
"ranges": [
{
"events": [
{
"introduced": "7.0.0"
},
{
"fixed": "7.5.6"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.5.6"
},
"package": {
"ecosystem": "PyPI",
"name": "jupyterlab"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.5.7"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 4.5.6"
},
"package": {
"ecosystem": "npm",
"name": "@jupyterlab/help-extension"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.5.7"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-40171"
],
"database_specific": {
"cwe_ids": [
"CWE-601",
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-30T17:25:47Z",
"nvd_published_at": "2026-05-06T20:16:31Z",
"severity": "HIGH"
},
"details": "### Impact\n\nA stored Cross-Site Scripting (XSS) vulnerability in Jupyter Notebook allows attackers to steal authentication tokens from users who open malicious notebook files and interact with elements that the attacker can make look indistinguishable from legitimate controls (single click interaction).\n\nThe vulnerability enables complete account takeover through the Jupyter REST API, allowing the attacker to:\n1. Read all files\n2. Modify/create files\n3. Access running kernels and execute arbitrary code\n4. Create terminals for shell access\n\n### Patches\n\nJupyter Notebook 7.5.6 and JupyterLab 4.5.7 include patches for this vulnerability.\n\n### Workarounds\n\nThe help extension can be disabled via CLI:\n\n```\njupyter labextension disable @jupyter-notebook/help-extension\njupyter labextension disable @jupyterlab/help-extension\n```\n\n### Hardening\n\nThe patched versions include a toggle to disable the command linker functionality altogether, for example via `overrides.json`:\n\n```json\n{\n \"@jupyterlab/apputils-extension:sanitizer\": {\n \"allowCommandLinker\": false\n }\n}\n```\n\n### Resources\n\n- https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files\n\n### Acknowledgments\n\nReported by Daniel Teixeira - NVIDIA AI Red Team",
"id": "GHSA-rch3-82jr-f9w9",
"modified": "2026-05-08T19:26:04Z",
"published": "2026-04-30T17:25:47Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/jupyter/notebook/security/advisories/GHSA-rch3-82jr-f9w9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40171"
},
{
"type": "PACKAGE",
"url": "https://github.com/jupyter/notebook"
},
{
"type": "WEB",
"url": "https://jupyterlab.readthedocs.io/en/latest/user/commands.html#commands-in-markdown-output-and-files"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "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",
"type": "CVSS_V4"
}
],
"summary": "Jupyter Notebook Vulnerable to Authentication Token Theft via CommandLinker XSS"
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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