JupyterLab up to 4.5.9/4.6.1 PyPI Extension Manager PyPIExtensionManager.install input validation

Summaryinfo

A vulnerability was found in JupyterLab up to 4.5.9/4.6.1. It has been classified as problematic. Affected by this issue is the function PyPIExtensionManager.install of the component PyPI Extension Manager. This manipulation causes input validation. This vulnerability is handled as CVE-2026-73626. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in JupyterLab up to 4.5.9/4.6.1. It has been declared as problematic. Affected by this vulnerability is the function PyPIExtensionManager.install of the component PyPI Extension Manager. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

JupyterLab versions >=4.6.0,<=4.6.1 and <=4.5.9 contain an allowlist/blocklist enforcement gap in PyPIExtensionManager.install(). A missing 'await' caused the is_install_allowed coroutine to never execute, so the extension allowlist/blocklist check was not enforced for direct callers of install(). The stock JupyterLab HTTP API and Extension Manager UI are not affected, as they perform a separate, correctly awaited check. The issue affects only deployments where a custom extension or downstream integration imports PyPIExtensionManager and calls install() directly with a package name influenced by untrusted input, an allowlist/blocklist is configured, the PyPI Extension Manager is enabled, and kernels and terminals are disabled or delegated to remote hosts. Fixed in JupyterLab 4.6.2 and 4.5.10.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-73626 since 08/13/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation needs additional levels of successful authentication. Technical details are known, but no exploit is available.

Upgrading to version 4.5.10 or 4.6.2 eliminates this vulnerability.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Name

• JupyterLab

Version

• 4.5.0
• 4.5.1
• 4.5.2
• 4.5.3
• 4.5.4
• 4.5.5
• 4.5.6
• 4.5.7
• 4.5.8
• 4.5.9
• 4.6.0
• 4.6.1

Website

• Product: https://github.com/jupyterlab/jupyterlab/

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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