BIT-jupyterlab-2026-42266: JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.
JupyterLab versions from 4.0.0 up to but not including 4.5.7 contain a vulnerability where the allow-list for extensions installable via the PyPI Extension Manager is not properly enforced. This allows installation of third-party extensions outside the intended default PyPI index via POST requests. The issue is fixed in version 4.5.7.
AI Analysis
Technical Summary
JupyterLab, an extensible interactive computing environment, has a security vulnerability (CVE-2026-42266) affecting versions 4.0.0 through 4.5.6. The vulnerability arises because the allow-list of extensions that can be installed from the PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced. Consequently, JupyterLab does not restrict extension installation to packages listed on the default PyPI index, enabling potential installation of malicious third-party extensions via crafted POST requests. This discrepancy between the Extension Manager API and GUI policy is resolved in version 4.5.7.
Potential Impact
The vulnerability allows an attacker to bypass the intended allow-list restrictions and install arbitrary third-party extensions in JupyterLab. This could lead to execution of malicious code or compromise of the JupyterLab environment. No known exploits in the wild have been reported. The severity is assessed as high due to the potential for unauthorized extension installation.
Mitigation Recommendations
An official fix is available in JupyterLab version 4.5.7. Users should upgrade to version 4.5.7 or later to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.
BIT-jupyterlab-2026-42266: JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.
Description
JupyterLab versions from 4.0.0 up to but not including 4.5.7 contain a vulnerability where the allow-list for extensions installable via the PyPI Extension Manager is not properly enforced. This allows installation of third-party extensions outside the intended default PyPI index via POST requests. The issue is fixed in version 4.5.7.
Affected software
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
JupyterLab, an extensible interactive computing environment, has a security vulnerability (CVE-2026-42266) affecting versions 4.0.0 through 4.5.6. The vulnerability arises because the allow-list of extensions that can be installed from the PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced. Consequently, JupyterLab does not restrict extension installation to packages listed on the default PyPI index, enabling potential installation of malicious third-party extensions via crafted POST requests. This discrepancy between the Extension Manager API and GUI policy is resolved in version 4.5.7.
Potential Impact
The vulnerability allows an attacker to bypass the intended allow-list restrictions and install arbitrary third-party extensions in JupyterLab. This could lead to execution of malicious code or compromise of the JupyterLab environment. No known exploits in the wild have been reported. The severity is assessed as high due to the potential for unauthorized extension installation.
Mitigation Recommendations
An official fix is available in JupyterLab version 4.5.7. Users should upgrade to version 4.5.7 or later to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- BIT-jupyterlab-2026-42266
- Osv Schema Version
- 1.6.2
- Aliases
- ["CVE-2026-42266"]
- Ecosystems
- ["Bitnami"]
- Database Specific Severity
- High
- Cvss Version
- null
Threat ID: 6a4c347727e9c79719604232
Added to database: 07/06/2026, 23:04:23 UTC
Last enriched: 07/06/2026, 23:37:40 UTC
Last updated: 07/21/2026, 20:57:07 UTC
Views: 18
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