Invalid input to login resulted in unbounded logging output. Only form-based Authenticators (the default PAM Authenticator, but not the more widely used OAuthenticator) are affected.
JupyterHub's XSRF protection (updated in 4.1.0) inappropriately treated requests with Sec-Fetch-Mode: no-cors as same-origin requests, which they are not, bypassing XSRF checks. The JSON API is not affected, only HTTP form endpoints, such as /hub/spawn and /hub/accept-share, meaning attackers could trigger server spawn (but not access the server) and if the attacker is a JupyterHub user permitted to share access to their server, cause a user to accept a share …
An open redirect vulnerability in JupyterHub <=5.4.3 allows attackers to construct links which, when clicked, take users to the JupyterHub login page, after which they are sent to an arbitrary attacker-controlled site outside JupyterHub instead of a JupyterHub page, bypassing JupyterHub's check to prevent this.
If a user is granted the admin:users scope, they may escalate their own privileges by making themselves a full admin user.
Affected configurations: Single-origin JupyterHub deployments JupyterHub deployments with user-controlled applications running on subdomains or peer subdomains of either the Hub or a single-user server. 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 the following: Full access to JupyterHub API and user's single-user server, e.g. Create and exfiltrate …
JupyterHub 1.1.0 allows CSRF in the admin panel via a request that lacks an _xsrf field, as demonstrated by a /hub/api/user request (to add or remove a user account).
Users of JupyterLab with JupyterHub who have multiple JupyterLab tabs open in the same browser session, may see incomplete logout from the single-user server, as fresh credentials (for the single-user server only, not the Hub) reinstated after logout, if another active JupyterLab session is open while the logout takes place.
An Open Redirect vulnerability for all browsers in Jupyter Notebook before 5.7.7 and some browsers in JupyterHub before 0.9.5 allows crafted links to the login page, which will redirect to a malicious site after successful login. Servers running on a base_url prefix are not affected.