nbgrader is a system for assigning and grading notebooks. Enabling frame-ancestors: 'self' grants any JupyterHub user the ability to extract formgrader content by sending malicious links to users with access to formgrader, at least when using the default JupyterHub configuration of `enable_subdomains = False`. #1915 disables a protection which would allow user Alice to craft a page embedding formgrader in an IFrame. If Bob visits that page, his credentials will be sent and the formgrader page loaded. Because Alice's page is on the same Origin as the formgrader iframe, Javasript on Alice's page has _full access_ to the contents of the page served by formgrader using Bob's credentials. This issue has been addressed in release 0.9.5 and all users are advised to upgrade. Users unable to upgrade may disable `frame-ancestors: self`, or enable per-user and per-service subdomains with `JupyterHub.enable_subdomains = True` (then even if embedding in an IFrame is allowed, the host page does not…

jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. This 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. JupyterLab v3.6.8, v4.2.5 and Jupyter Notebook v7.2.2 have been patched to resolve this issue. Users are advised to upgrade. There is no workaround for the underlying DOM Clobbering susceptibility. However, select plugins can be disabled on deployments which cannot update in a timely fashion to minimise the risk. These are: 1. `@jupyterlab/mathjax-extension:plugin` - users will loose ability to preview mathematical equations. 2. `@jupyterlab/markdownviewer-extension:plugin` - users will loose ability to open Markdown previews. 3. `@jupyterlab/mathjax2-extension:plugin` (if…

JupyterHub is software that allows one to create a multi-user server for Jupyter notebooks. Prior to versions 4.1.6 and 5.1.0, if a user is granted the `admin:users` scope, they may escalate their own privileges by making themselves a full admin user. The impact is relatively small in that `admin:users` is already an extremely privileged scope only granted to trusted users. In effect, `admin:users` is equivalent to `admin=True`, which is not intended. Note that the change here only prevents escalation to the built-in JupyterHub admin role that has unrestricted permissions. It does not prevent users with e.g. `groups` permissions from granting themselves or other users permissions via group membership, which is intentional. Versions 4.1.6 and 5.1.0 fix this issue.

JupyterLab extension template is a `copier` template for JupyterLab extensions. Repositories created using this template with `test` option include `update-integration-tests.yml` workflow which has an RCE vulnerability. Extension authors hosting their code on GitHub are urged to upgrade the template to the latest version. Users who made changes to `update-integration-tests.yml`, accept overwriting of this file and re-apply your changes later. Users may wish to temporarily disable GitHub Actions while working on the upgrade. We recommend rebasing all open pull requests from untrusted users as actions may run using the version from the `main` branch at the time when the pull request was created. Users who are upgrading from template version prior to 4.3.0 may wish to leave out proposed changes to the release workflow for now as it requires additional configuration.

OAuthenticator is software that allows OAuth2 identity providers to be plugged in and used with JupyterHub. JupyterHub < 5.0, when used with `GlobusOAuthenticator`, could be configured to allow all users from a particular institution only. This worked fine prior to JupyterHub 5.0, because `allow_all` did not take precedence over `identity_provider`. Since JupyterHub 5.0, `allow_all` does take precedence over `identity_provider`. On a hub with the same config, now all users will be allowed to login, regardless of `identity_provider`. `identity_provider` will basically be ignored. This is a documented change in JupyterHub 5.0, but is likely to catch many users by surprise. OAuthenticator 16.3.1 fixes the issue with JupyterHub 5.0, and does not affect previous versions. As a workaround, do not upgrade to JupyterHub 5.0 when using `GlobusOAuthenticator` in the prior configuration.

Jupyter Server Proxy allows users to run arbitrary external processes alongside their notebook server and provide authenticated web access to them. Versions of 3.x prior to 3.2.4 and 4.x prior to 4.2.0 have a reflected cross-site scripting (XSS) issue. The `/proxy` endpoint accepts a `host` path segment in the format `/proxy/<host>`. When this endpoint is called with an invalid `host` value, `jupyter-server-proxy` replies with a response that includes the value of `host`, without sanitization [2]. A third-party actor can leverage this by sending a phishing link with an invalid `host` value containing custom JavaScript to a user. When the user clicks this phishing link, the browser renders the response of `GET /proxy/<host>`, which runs the custom JavaScript contained in `host` set by the actor. As any arbitrary JavaScript can be run after the user clicks on a phishing link, this issue permits extensive access to the user's JupyterLab instance for an actor. Patches are included in vers…

The Jupyter Server provides the backend for Jupyter web applications. Jupyter Server on Windows has a vulnerability that lets unauthenticated attackers leak the NTLMv2 password hash of the Windows user running the Jupyter server. An attacker can crack this password to gain access to the Windows machine hosting the Jupyter server, or access other network-accessible machines or 3rd party services using that credential. Or an attacker perform an NTLM relay attack without cracking the credential to gain access to other network-accessible machines. This vulnerability is fixed in 2.14.1.

Jupyter Scheduler is collection of extensions for programming jobs to run now or run on a schedule. The list of conda environments of `jupyter-scheduler` users maybe be exposed, potentially revealing information about projects that a specific user may be working on. This vulnerability has been patched in version(s) 1.1.6, 1.2.1, 1.8.2 and 2.5.2.

JupyterHub is an open source multi-user server for Jupyter notebooks. By tricking a user into visiting a malicious subdomain, the attacker can achieve an XSS directly affecting the former's session. More precisely, in the context of JupyterHub, this XSS could achieve full access to JupyterHub API and user's single-user server. The affected configurations are single-origin JupyterHub deployments and JupyterHub deployments with user-controlled applications running on subdomains or peer subdomains of either the Hub or a single-user server. This vulnerability is fixed in 4.1.0.

OAuthenticator provides plugins for JupyterHub to use common OAuth providers, as well as base classes for writing one's own Authenticators with any OAuth 2.0 provider. `GoogleOAuthenticator.hosted_domain` is used to restrict what Google accounts can be authorized access to a JupyterHub. The restriction is intented to be to Google accounts part of one or more Google organization verified to control specified domain(s). Prior to version 16.3.0, the actual restriction has been to Google accounts with emails ending with the domain. Such accounts could have been created by anyone which at one time was able to read an email associated with the domain. This was described by Dylan Ayrey (@dxa4481) in this [blog post] from 15th December 2023). OAuthenticator 16.3.0 contains a patch for this issue. As a workaround, restrict who can login another way, such as `allowed_users` or `allowed_google_groups`.