JupyterLab has an Extension Manager API/GUI Policy Discrepancy, allowing 3rd party (malicious) extensions install via POST request
Published May 13, 2026 · Updated Oct 23, 2026 · Also known as GHSA-37w4-hwhx-4rc4, PYSEC-2026-164, BIT-jupyterlab-2026-42266
Original summary
Normalized public record · Updated Oct 23, 2026
JupyterLab has an Extension Manager API/GUI Policy Discrepancy, allowing 3rd party (malicious) extensions install via POST request
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
The allow-list of extensions that can be installed from PyPI Extension Manager (`allowed_extensions_uris`) is not correctly enforced by JupyterLab prior to 4.5.7. The PyPI Extension Manager was not contained to packages listed on the default PyPI index.
Potential impact
An authenticated attacker - such as a student in a shared JupyterHub environment or a user in a multi-tenant JupyterLab deployment - can escalate their privileges. This might allow for data exfiltration, lateral movement within the network, and persistent compromise of the server infrastructure.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- 10%
- Aliases
- GHSA-37w4-hwhx-4rc4, PYSEC-2026-164, BIT-jupyterlab-2026-42266
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
- Security advisory ↗
- Source repository ↗
- https://jupyterhub.readthedocs.io/en/5.2.1/explanation/websecurity.html ↗
- https://jupyterlab.readthedocs.io/en/latest/user/extensions.html#extension-manager-implementations ↗
- access.redhat.com ↗
- access.redhat.com ↗
- access.redhat.com ↗
- bugzilla.redhat.com ↗
- security.access.redhat.com ↗
Record history
Published May 13, 2026 · Last refreshed Oct 23, 2026