CVE-2026-73417 JupyterLab: Cross-site scripting (XSS) via crafted settings file (`overrides.json`)
Attackers can execute arbitrary code via crafted settings files in JupyterLab, allowing them to read or modify notebooks and run code on connected kernels.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-73417?
CVE-2026-73417 is a high-severity cross-site scripting vulnerability in jupyterlab, published on 13 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From 3.3.0 until 4.5.10 and 4.6.2, JupyterLab allows notebook settings to be shared and applied through an overrides.json file using the Import button in the Settings Editor. In packages/notebook-extension/schema/tracker.json and packages/notebook-extension/src/index.ts, the sideBySideLeftMarginOverride and sideBySideRightMarginOverride settings are not properly validated before being inserted into style content, allowing a crafted settings file to contain instructions that execute as code instead of only changing display preferences. A user can import the malicious file, or an attacker with access to a shared settings location can plant an overrides.json that is applied automatically. The embedded code runs with the affected user's access and can read or modify notebooks and files and run code through the notebook server, including on a connected kernel. This issue is fixed in versions 4.5.10 and 4.6.2.
Which versions are affected by CVE-2026-73417?
6 open source packages ship an affected version, including jupyterlab.
| Package | Affected | Fixed in |
|---|---|---|
jupyterlab Bitnami | From 3.3.0 | 4.5.10, 4.6.2 |
jupyterlab PyPI | From 3.3.0 | 4.5.10, 4.6.2 |
jupyterlab PyPI | From 3.3.0 | 4.5.10 |
jupyterlab PyPI | From 3.3.0 | 4.5.10 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
jupyterlab PyPI | From 4.6.0 | 4.6.2 |
How do I fix CVE-2026-73417?
Upgrade jupyterlab to a fixed version for your release line: 4.5.10 or 4.6.2.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-73417 being exploited?
There is no known exploitation of CVE-2026-73417 in the wild and no public exploit code.
Sources
Also known as BIT-jupyterlab-2026-73417, CLEANSTART-2026-JZ86635, DEBIAN-CVE-2026-73417, GHSA-pppj-hq3g-57pj, MINI-pg34-3q6m-r22c, PYSEC-2026-3672 and 1 more.