CVE-2026-73416 jupyterlab: PyPI extension blocklist package-name canonicalization bypass
Authenticated users can bypass PyPI extension blocklists by using non-canonical package names, allowing installation of prohibited extensions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-73416?
CVE-2026-73416 is a medium-severity vulnerability in jupyterlab, published on 13 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 4.5.0 until 4.5.10 and 4.6.2, in jupyterlab/extensions/manager.py and jupyterlab/extensions/pypi.py, JupyterLab's PyPI extension manager enforces blocked_extensions_uris by comparing requested install names to blocklist entries with custom normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as JupyterLab.Git for a blocklisted package such as jupyterlab-git, and JupyterLab accepts the install request even though pip resolves the variant to the same package. Security impact requires an allowlist or blocklist intended to restrict package installation, the PyPI Extension Manager, and kernels and terminals that are disabled or delegated to remote hosts. The bypass lets an authenticated user install a prohibited extension, defeat integrity restrictions, and affect availability without gaining new read access. This issue is fixed in versions 4.5.10 and 4.6.2.
Which versions are affected by CVE-2026-73416?
6 open source packages ship an affected version, including jupyterlab.
| Package | Affected | Fixed in |
|---|---|---|
jupyterlab Bitnami | From 4.5.0 | 4.5.10, 4.6.2 |
jupyterlab PyPI | From 4.5.0 | 4.5.10, 4.6.2 |
jupyterlab PyPI | From 4.5.0 | 4.5.10 |
jupyterlab PyPI | From 4.5.0 | 4.5.10 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
How do I fix CVE-2026-73416?
Upgrade jupyterlab to a fixed version for your release line: 4.5.10 or 4.6.2.
Is CVE-2026-73416 being exploited?
There is no known exploitation of CVE-2026-73416 in the wild and no public exploit code.
Sources
Also known as BIT-jupyterlab-2026-73416, CLEANSTART-2026-NU47623, DEBIAN-CVE-2026-73416, GHSA-89vp-jrxv-24w8, MINI-wqr5-wfg6-wf3h, PYSEC-2026-3670 and 1 more.