CVE-2026-73626 PUBLISHED

JupyterLab before 4.6.2 Authentication Bypass via PyPIExtensionManager

Assigner: VulnCheck
Reserved: 13.08.2026 Published: 13.08.2026 Updated: 13.08.2026

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.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:N/SI:N/SA:N
CVSS Score: 0

Product Status

Vendor jupyterlab
Product jupyterlab
Versions Default: unaffected
  • affected from 4.6.0 to 4.6.1 (excl.)
  • Version 4.6.1 is unaffected
Vendor jupyterlab
Product jupyterlab
Versions Default: unaffected
  • affected from 0 to 4.5.10 (excl.)
  • Version 4.5.10 is unaffected

Credits

  • de3erve-hunter reporter
  • MUFFANUJ finder
  • krassowski coordinator

References

Problem Types

  • Improper Access Control CWE