jupyterlab-git excluded_paths Case-Sensitivity Bypass Allows Reading Excluded Directories

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.1 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

EPSS

• CVE-2026-54528: 0.41% estimated exploitation activity in the next 30 days; percentile 35.38 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary jupyterlab-git 0.53.0 (latest, 2026-04-30) uses fnmatch.fnmatchcase() in GitHandler.prepare() (jupyterlabgit/handlers.py:91) to enforce the admin-configured excludedpaths security control. Because fnmatchcase is unconditionally case-sensitive, an authenticated user on a case-insensitive filesystem (macOS APFS, Windows NTFS) can bypass the exclusion by varying the case of the URL path segment — e.g. requesting /git/project/Secrets/... instead of /git/project/secrets/... — gaining read access to git history, file content, and status in directories the administrator explicitly excluded. Vulnerable Code Root Cause fnmatch.fnmatchcase() is unconditionally case-sensitive regardless of the operating system. Contrast with fnmatch.fnmatch() which normalizes via os.path.normcase() on case-insensitive platforms. On macOS APFS and Windows NTFS, /project/Secrets and /project/secrets resolve to the same directory on disk. The exclusion check rejects only the exact-case match, but the…

Published by the source

19 Jun 2026, 19:36 UTC

Last modified by the source

13 Jul 2026, 16:42 UTC

Source last checked

26 Oct 2026, 13:46 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-436q-jwfr-rm2h

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-436q-jwfr-rm2h

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# Patch Next advisory brief: CVE-2026-54528

Advisory: jupyterlab-git excluded_paths Case-Sensitivity Bypass Allows Reading Excluded Directories
IDs: CVE-2026-54528, GHSA-436q-jwfr-rm2h
Record: https://patchnext.com/advisories/cve-2026-54528 (revision 2, source checked 26 Oct 2026, 13:46 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: jupyterlab-git 0.54.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI jupyterlab-git: affected <= 0.53.0; fixed in 0.54.0

## Suggested inspection (read-only)
- `python -m pip show jupyterlab-git`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on jupyterlab-git.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-436q-jwfr-rm2h (OSV record GHSA-436q-jwfr-rm2h lists affected ranges: PyPI jupyterlab-git >=0 <0.54.0 (fixed))
- Verified: https://github.com/advisories/GHSA-436q-jwfr-rm2h (GitHub-reviewed advisory GHSA-436q-jwfr-rm2h lists affected ranges: PyPI jupyterlab-git >=0 <=0.53.0)

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