CVE-2026-54528: JupyterLab Git case-sensitivity bypass in excluded_paths

CVE-2026-54528 · Severity: high · CVSS 7.1 · Published 2026-07-08

JupyterLab Git is an extension that allows users to manage Git repositories directly within the JupyterLab interface. A security flaw in how the extension handles file path restrictions allows authenticated users to bypass access controls on systems with case-insensitive filesystems (such as Windows or macOS). By simply changing the capitalization of a folder name in a web request, an attacker can view sensitive files, git history, and source code that administrators intended to keep hidden.

Technologies: jupyterlab-git (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2026-54528 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-54528 being exploited in the wild.
How severe is CVE-2026-54528?
High severity, with a CVSS score of 7.1, published 8 July 2026.
Which products and versions are affected?
jupyterlab-git (PyPI) <= 0.53.0, ECOSYSTEM:introduced=0,fixed=0.54.0.
Is there a fix for CVE-2026-54528?
Yes. jupyterlab-git (PyPI): upgrade to 0.54.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-54528 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-54528?
Check whether you run jupyterlab-git (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • jupyterlab-git (PyPI): upgrade to 0.54.0 or later
    pip install "jupyterlab-git>=0.54.0"

Technical details

The vulnerability exists in the GitHandler.prepare() method within jupyterlab_git/handlers.py. The extension uses fnmatch.fnmatchcase() to validate requested paths against an admin-defined 'excluded_paths' list. Because fnmatchcase() is strictly case-sensitive, it fails to block requests where the path casing is modified (e.g., '/Secrets/' instead of '/secrets/'). On case-insensitive filesystems like NTFS (Windows) or APFS (macOS), these varied paths resolve to the same underlying directory. An authenticated attacker can exploit this to bypass security controls and access the /content, /status, and /diff endpoints for restricted directories. The issue is resolved in version 0.54.0 by implementing case-folding during the comparison.

Affected products

  • jupyterlab jupyterlab-git < 0.54.0

Identifiers

  • CVE-2026-54528
  • GHSA-436q-jwfr-rm2h
  • PYSEC-2026-2539

Timeline

  • 2026-06-17: patched: Version 0.54.0 released
  • 2026-06-18: advisory: GitHub Security Advisory published
  • 2026-07-08: disclosed: CVE published to NVD

References

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