PYSEC-2026-1706 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...

Permissive Regular Expression

Overview Affected versions of this package are vulnerable to Permissive Regular Expression in the use of re.match to verify alloworiginpat values. This allows an attacker to bypass intended CORS restrictions and gain unauthorized access to sensitive API responses. Code execution is possible by...

Insufficient Session Expiration

Overview Affected versions of this package are vulnerable to Insufficient Session Expiration due to jupytercookiesecret never being automatically rotated or cleared. An attacker can keep or reuse authenticated session cookies after a password change by presenting a cookie signed with a secret tha...

Regular Expression without Anchors

Overview Affected versions of this package are vulnerable to Regular Expression without Anchors through the alloworiginpat checks in websocket.py, login.py. An attacker can bypass CORS, WebSocket origin checks, and login redirect validation by supplying an Origin or Referer value that matches the...

Information Exposure

Overview Affected versions of this package are vulnerable to Information Exposure through the logrequest function. This function recorded sensitive information from the query parameters without improper sanitization. Remediation Upgrade jupyter-server to version 1.23.6, 2.3.0 or higher. Reference...