How severe is GHSA-fcr8-4r9f-r66m?

No CVSS score has been assigned to GHSA-fcr8-4r9f-r66m yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-fcr8-4r9f-r66m?

GHSA-fcr8-4r9f-r66m affects the following packages: nbgrader (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-fcr8-4r9f-r66m?

Update nbgrader to 0.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fcr8-4r9f-r66m is resolved across your whole dependency graph.

How do I detect GHSA-fcr8-4r9f-r66m in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbgrader, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-fcr8-4r9f-r66m if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is GHSA-fcr8-4r9f-r66m actively exploited in the wild?

No public exploit code has been indexed for GHSA-fcr8-4r9f-r66m yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-fcr8-4r9f-r66m?

GHSA-fcr8-4r9f-r66m has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 42th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-fcr8-4r9f-r66m?

GHSA-fcr8-4r9f-r66m is classified as CWE-668 (CWE-668). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-fcr8-4r9f-r66m published, and has it been updated?

GHSA-fcr8-4r9f-r66m was published on January 17, 2025 and was last updated on July 7, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍 PyPI

Not in CISA KEV

nbgrader's `frame-ancestors: self` grants all users access to formgraderGHSA-fcr8-4r9f-r66m

Fix: jupyter/nbgrader#1915

GHSA-fcr8-4r9f-r66m is a CWE-668 vulnerability in nbgrader. A fix is available for nbgrader — see the affected versions and patch details below.

Also known asCVE-2025-23205PYSEC-2026-1692

Published

Jan 17, 2025

Updated

Jul 7, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-fcr8-4r9f-r66m.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs42th percentile — riskier than 42% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐍nbgrader

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

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.

Workarounds

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).

References

JupyterHub documentation on why and when frame-ancestors: self is insecure, and why it was disabled by default: https://jupyterhub.readthedocs.io/en/stable/explanation/websecurity.html#:~:text=frame-ancestors

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`nbgrader`	≥ 0.9.4&&< 0.9.5	0.9.5`pip install --upgrade 'nbgrader==0.9.5'`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for nbgrader, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update nbgrader to 0.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-fcr8-4r9f-r66m is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Impact 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 pag

O3 Security · Impact-Aware SCA

Is GHSA-fcr8-4r9f-r66m in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works