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CVE-2025-23205GHSA-FCR8-4R9F-R66MPYSEC-2026-1692

`frame-ancestors: self` grants all users access to formgrader in nbgrader

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 0.9.5
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

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 have access to the contents of the frame).

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • jupyter nbgrader

    0.9.4

  • nbgraderPyPI

    From 0.9.4 · fixed in 0.9.5

References 4

GitHub · jupyter/nbgrader

jupyterhub.readthedocs.io