GHSA-9f66-54xg-pc2c is a medium-severity (CVSS 6.1) Open Redirect vulnerability in jupyter-server. 1 public exploit reference exists, so weaponization risk is real. O3 Security confirms whether GHSA-9f66-54xg-pc2c is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Jupyter Server open redirect vulnerability
Real-World Exposure
jupyter-serverReal-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
What kind of vulnerability is it? Who is impacted?
Open redirect vulnerability - a maliciously crafted link to a jupyter server could redirect the browser to a different website.
All jupyter servers running without a base_url prefix are technically affected, however, these maliciously crafted links can only be reasonably made for known jupyter server hosts. A link to your jupyter server may appear safe, but ultimately redirect to a spoofed server on the public internet. This same vulnerability was patched in upstream notebook v5.7.8.
Patches
Has the problem been patched? What versions should users upgrade to?
Patched in jupyter_server 1.1.1. If upgrade is not available, a workaround can be to run your server on a url prefix:
jupyter server --ServerApp.base_url=/jupyter/
References
For more information
If you have any questions or comments about this advisory, or vulnerabilities to report, please email our security list [email protected].
Credit: Yaniv Nizry from CxSCA group at Checkmarx
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | jupyter-server | all versions | 1.1.1 |
Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for jupyter-server. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update jupyter-server to 1.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9f66-54xg-pc2c 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.
How O3 protects you
O3 pinpoints whether GHSA-9f66-54xg-pc2c is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-9f66-54xg-pc2c. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-9f66-54xg-pc2c in your dependencies?
O3 detects GHSA-9f66-54xg-pc2c across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.