CVE-2026-73626: Improper Access Control

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 isinstallallowed coroutine to never execute, so the extension allowlist/blocklist check was not enforced for direct callers of install. The sto...