Bug 2498291 (CVE-2026-54528)

Summary: CVE-2026-54528 jupyterlab-git: JupyterLab Git: Information disclosure via case-sensitivity bypass in excluded path enforcement
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in JupyterLab Git, a Git extension for JupyterLab. This vulnerability allows an authenticated user on a case-insensitive filesystem to bypass administrator-configured excluded paths by varying the case of the URL path segment. This bypass enables the user to read file content, view git status, logs, and diffs, and enumerate commits within directories that were intended to be excluded. The root cause is the unconditional case-sensitivity of the `fnmatch.fnmatchcase()` function used for path enforcement, which does not normalize paths for case-insensitive platforms.
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Description OSIDB Bzimport 2026-07-08 22:02:11 UTC 
JupyterLab Git is a Git extension for JupyterLab. Prior to 0.54.0, jupyterlab-git uses fnmatch.fnmatchcase() in GitHandler.prepare() in jupyterlab_git/handlers.py to enforce excluded_paths, allowing an authenticated user on a case-insensitive filesystem to vary URL path casing and read excluded directories. This issue is fixed in version 0.54.0.