CVE-2026-73626: Jupyterlab

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

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.

Affected products

• Jupyterlab Jupyterlab: from 4.6.0, before 4.6.1 (fixed in 4.6.1); before 4.5.10 (fixed in 4.5.10)

Published 2026-08-13. Last modified 2026-09-09.