Answer in brief
CVE-2026-42266 records a High severity (CVSS 8.8) vulnerability in JupyterLab has an Extension Manager API/GUI Policy Discrepancy allowing 3rd party (malicious) extensions install via POST request.. The current sources do not mark it as known exploited. The current feed maps jupyterlab/jupyterlab (generic), jupyterlab (pip). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps jupyterlab/jupyterlab (generic), jupyterlab (pip). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| jupyterlab/jupyterlabgeneric | >= 4.0.0, < 4.5.7 | Not reported |
| jupyterlabpip | >=4.0.0,<=4.5.6 | 4.5.7 |
Published upstream
May 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 28, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.0.0 to 4.5.6, the allow-list of extensions that can be installed from PyPI Extension Manager (allowed_extensions_uris) is not correctly enforced by JupyterLab. The PyPI Extension Manager was not contained to packages listed on the default PyPI index. This vulnerability is fixed in 4.5.7.
Quoted source text, attributed separately from HOL analysis.