GHSA-RCH3-82JR-F9W9
Vulnerability from github – Published: 2026-04-30 17:25 – Updated: 2026-05-08 19:26Impact
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
{
"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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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.
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
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