JupyterLab: Image viewer allows XSS when opening malicious image in new browser tab

JupyterLab's image viewer allows for cross-site scripting XSS when a specially-crafted image file is opened through the image viewer and then opened in a new tab. This XSS issue can be used to cause remote code execution RCE on the JupyterLab server. Impact This vulnerability allows for arbitrary...

Incorrect Behavior Order: Validate Before Canonicalize

Overview jupyterlab is a JupyterLab computational environment. Affected versions of this package are vulnerable to Incorrect Behavior Order: Validate Before Canonicalize when enforcing blocklists for extension installation due to insufficient normalization of package names. An attacker can bypass...

JupyterLab: PyPI extension blocklist package-name canonicalization bypass

JupyterLab's PyPI extension manager enforces blockedextensionsuris by comparing the requested install name to blocklist entries with a custom string normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as...

GHSA-89VP-JRXV-24W8 JupyterLab: PyPI extension blocklist package-name canonicalization bypass

JupyterLab's PyPI extension manager enforces blockedextensionsuris by comparing the requested install name to blocklist entries with a custom string normalization that is weaker than PyPI package-name canonicalization. An authenticated user can request a PyPI-equivalent spelling such as...

Incorrect Authorization

Overview jupyterlab is a JupyterLab computational environment. Affected versions of this package are vulnerable to Incorrect Authorization in the enforcement of plugin manager lock rules via direct API requests to /lab/api/plugins. An attacker can circumvent administrative restrictions on enablin...

GHSA-WHVH-WF3X-G77J JupyterLab: Allowlist/blocklist check in `PyPIExtensionManager.install()` not enforced for direct callers (missing `await`)

The extension allowlist/blocklist check inside PyPIExtensionManager.install was not enforced due to a missing await. For purposes of JupyterLab this was a secondary defense-in-depth check: install was intended to enforce the allowlist/blocklist itself for any future uses and users calling this...

Not Failing Securely ('Failing Open')

Overview jupyterlab is a JupyterLab computational environment. Affected versions of this package are vulnerable to Not Failing Securely 'Failing Open' in the install function of PyPIExtensionManager when the allowlist/blocklist check is not properly enforced due to a missing await. An attacker ca...

PT-2026-71917

Name of the Vulnerable Software and Affected Versions jupyterlab versions 4.5.0 through 4.5.9 jupyterlab versions 4.6.0 through 4.6.1 Description The PyPI extension manager in JupyterLab fails to properly enforce blocked extensions uris because it uses a custom normalization process that is weake...

PT-2026-71454

Name of the Vulnerable Software and Affected Versions JupyterLab versions 4.6.0 through 4.6.1 JupyterLab versions 4.5.0 through 4.5.9 Description An enforcement gap exists in the PyPIExtensionManager.install function due to a missing await keyword, which prevents the is install allowed coroutine...

PT-2026-71310

Name of the Vulnerable Software and Affected Versions JupyterLab versions prior to 4.5.10 JupyterLab versions prior to 4.6.2 Description The ImageViewer component in packages/imageviewer/src/widget.ts uses URL.createObjectURL for specially crafted SVG images and revokes the blob URL prematurely...

PT-2026-71918

Name of the Vulnerable Software and Affected Versions JupyterLab versions 3.3.0 through 4.5.9 JupyterLab versions 4.6.0 through 4.6.1 Description JupyterLab allows notebook settings to be shared and applied via an overrides.json file through the Settings Editor Import button. The...

PYSEC-2026-2540 jupyterlab-git extension: Stored XSS leading to RCE

Overview Amazon Web Services AWS Security has identified a stored cross-site scripting XSS issue in the jupyterlab-git JupyterLab extension that can lead to remote code execution RCE. The issue exists in the PlainTextDiff.ts component, where the createHeader method passes Git filenames directly t...

PYSEC-2026-2541 jupyterlab-git extension: Stored XSS leading to RCE

Overview Amazon Web Services AWS Security has identified a stored cross-site scripting XSS issue in the jupyterlab-git JupyterLab extension that can lead to remote code execution RCE. The issue exists in the PlainTextDiff.ts component, where the createHeader method passes Git filenames directly t...

PYSEC-2026-2539 jupyterlab-git excluded_paths Case-Sensitivity Bypass Allows Reading Excluded Directories

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 filesyste...

PYSEC-2026-2681 JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content

JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with ...

PYSEC-2026-2537 JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content

JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with ...

PYSEC-2026-2535 JupyterLab vulnerable to SXSS in Markdown Preview

Impact The vulnerability depends on user interaction by opening a malicious notebook with Markdown cells, or Markdown file using JupyterLab preview feature. A malicious user can access any data that the attacked user has access to as well as perform arbitrary requests acting as the attacked user...

PYSEC-2026-2534 JupyterLab vulnerable to potential authentication and CSRF tokens leak

Impact Users of JupyterLab who click on a malicious link may get their Authorization and XSRFToken tokens exposed to a third party when running an older jupyter-server version. Patches JupyterLab 4.1.0b2, 4.0.11, and 3.6.7 were patched. Workarounds No workaround has been identified, however users...

Arbitrary Command Execution

GitHub CLI is vulnerable to Arbitrary Command Execution. The vulnerability is due to insufficient validation of JupyterLab URLs returned by a Codespace, where attacker-controlled non-loopback URLs such as vscode:// are passed to VS Code, allowing malicious Codespaces to execute arbitrary commands...

CVE-2026-54528

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, vi...