CVE-2026-54527 JupyterLab Git: Stored XSS leading to RCE
Attackers can execute arbitrary JavaScript and potentially code by crafting Git filenames viewed in the JupyterLab Git History tab.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-54527?
CVE-2026-54527 is a critical cross-site scripting vulnerability in jupyterlab-git, published on 8 Jul 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
JupyterLab Git is a Git extension for JupyterLab. From 0.30.0b3 before 0.54.0, the PlainTextDiff.ts createHeader() method passes Git filenames directly to innerHTML when rendering renamed files in commit history, allowing a crafted filename to execute JavaScript when a victim views the rename diff in the Git History tab. This issue is fixed in version 0.54.0.
Weakness: CWE-79
Which versions are affected by CVE-2026-54527?
8 open source packages ship an affected version, including jupyterlab-git, jupyterlab-git-core and @jupyterlab/git. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
jupyterlab-git PyPI | From 0.30.0b3 | 0.54.0 |
jupyterlab-git PyPI | From 0.30.0b3 | 0.54.0 |
jupyterlab-git PyPI | From 0.30.0b3 | 0.54.0 |
jupyterlab-git-core PyPI | From 0.30.0b3 | 0.54.0 |
jupyterlab-git-core PyPI | From 0.30.0b3 | 0.54.0 |
jupyterlab-git-core PyPI | From 0.30.0b3 | 0.54.0 |
2 more packages
@jupyterlab/git npm | From 0.30.0-beta.3 | 0.54.0 |
@jupyterlab/git npm | From 0.30.0-beta.3 | 0.54.0 |
Products include Jupyter Jupyterlab-Git.
How do I fix CVE-2026-54527?
Upgrade jupyterlab-git to 0.54.0 or later.
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-2026-54527 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54527 exists.
Other vulnerabilities in jupyterlab-git
Sources
Also known as GHSA-f962-v9hr-pfg5, PYSEC-2026-2540, PYSEC-2026-2541.