CVE-2021-32797 is a critical-severity (CVSS 9.6) Cross-site Scripting (XSS) vulnerability in jupyterlab. 1 public exploit reference exists, so weaponization risk is real. A fix is available for jupyterlab — see the affected versions and patch details below.
JupyterLab: XSS due to lack of sanitization of the action attribute of an html <form>
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-32797 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
jupyterlab🐍jupyterlab🐍jupyterlab🐍jupyterlab🐍jupyterlab🐍notebook🐍notebookReal-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
Untrusted notebook can execute code on load. This is a remote code execution, but requires user action to open a notebook.
Patches
Patched in the following versions: 3.1.4, 3.0.17, 2.3.2, 2.2.10, 1.2.21.
References
OWASP Page on Restricting Form Submissions
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: Guillaume Jeanne from Google
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | jupyterlab | all versions | 1.2.21pip install --upgrade 'jupyterlab==1.2.21' |
| 🐍PyPI | jupyterlab | ≥ 2.0.0a0&&< 2.2.10 | 2.2.10pip install --upgrade 'jupyterlab==2.2.10' |
| 🐍PyPI | jupyterlab | ≥ 2.3.0a0&&< 2.3.2 | 2.3.2pip install --upgrade 'jupyterlab==2.3.2' |
| 🐍PyPI | jupyterlab | ≥ 3.0.0a0&&< 3.0.17 | 3.0.17pip install --upgrade 'jupyterlab==3.0.17' |
| 🐍PyPI | jupyterlab | ≥ 3.1.0a0&&< 3.1.4 | 3.1.4pip install --upgrade 'jupyterlab==3.1.4' |
| 🐍PyPI | notebook | all versions | 5.7.11pip install --upgrade 'notebook==5.7.11' |
Affected Products
jupyterlabjupyterResearch 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 jupyterlab, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update jupyterlab to 1.2.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32797 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.
Frequently Asked Questions
Is CVE-2021-32797 in your dependencies?
Find it across PyPI, including transitive dependencies.