CVE-2026-102832

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Stored XSS in JupyterLab via Trusted Markdown Execution

Publication date: 2026-10-13

Last updated on: 2026-10-16

Assigner: GitHub, Inc.

Description

JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.5.7 until 4.5.11 and 4.6.4, the markdownviewer:trust and notebook:trust command-link handlers use tracker.currentWidget to resolve the current Markdown viewer or notebook when the user answers rather than retaining the document whose command button was clicked. If another document becomes current while the prompt is open and the user chooses Trust, JupyterLab marks the second document trusted while leaving the clicked document untrusted. Later command buttons in the incorrectly trusted document run without a prompt, and trusting a notebook marks all cells trusted, saves unsaved edits, and persists the server signature to disk. Applications that bundle JupyterLab, including affected Notebook and JupyterLite releases, inherit the behavior. This issue is fixed in versions 4.5.11 and 4.6.4.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-13

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-13

EPSS Evaluated

2026-10-18

NVD

CVE-2026-102832

EUVD

EUVD-2026-98809

Affected Vendors & Products

Vendor	Product	Version / Range
jupyterlab	jupyterlab	>= 4.5.7, < 4.5.11
jupyterlab	jupyterlab	>= 4.6.0, < 4.6.4
jupyterlab	jupyterlite-core	>= 0.7.5, < 0.8.4
jupyterlab	notebook	>= 7.5.6, < 7.6.3

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-367	The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.
CWE-863	The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

Attack-Flow Graph

Executive Summary

This vulnerability in JupyterLab (CVE-2026-102832) involves a race condition where trusting a command link in one document incorrectly marks another active document as trusted. When a user clicks a command button and a prompt appears, if another document becomes active before the user responds, the new document is trusted instead of the intended one. This allows future commands in the unintended document to run without prompts, potentially executing malicious actions silently.

Detection Guidance

This vulnerability is specific to JupyterLab versions 4.5.7 to 4.6.3 and can be detected by checking the installed version of JupyterLab. Run: pip show jupyterlab. If the version is between 4.5.7 and 4.6.3, the system is vulnerable.

Impact Analysis

If exploited, this vulnerability could allow an attacker to trick you into trusting a malicious document. Commands in that document would then execute without further prompts, potentially running harmful code on your system. For notebooks, this also marks all cells as trusted and saves unsaved edits, embedding the change permanently.

Compliance Impact

This vulnerability could potentially impact compliance with GDPR and HIPAA by allowing unauthorized command execution through trusted notebooks or markdown files. If malicious commands run silently due to incorrect trust boundaries, it may lead to unauthorized data access, modification, or exfiltration, violating confidentiality and integrity requirements under these regulations.

Mitigation Strategies

Upgrade JupyterLab to version 4.6.4 or later using: pip install --upgrade jupyterlab.
If upgrading is not possible, disable the command linker feature as a workaround.
Avoid clicking Trust buttons in prompts; use Run Once instead to prevent unintended trust assignments.

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