CVE-2026-54527: JupyterLab Git: Stored XSS leading to RCE

Severity: critical (CVSS 9.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-07-08 · updated 2026-10-25
Weakness: CWE-79

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.

Affected products

jupyterlab-git: from 0.30.1 before 0.54.0; 0.30.0, 0.30.0-beta3 — fixed in 0.54.0

How to fix

Upgrade to a fixed version: jupyterlab-git 0.54.0. Check the vendor advisory for mitigations.

References

https://github.com/jupyterlab/jupyterlab-git/commit/c6d37b88f36aa59aee317930b95e427fb9d6b09b
https://github.com/jupyterlab/jupyterlab-git/releases/tag/v0.54.0
https://github.com/jupyterlab/jupyterlab-git/security/advisories/GHSA-f962-v9hr-pfg5
https://github.com/jupyterlab/jupyterlab-git/security/advisories/GHSA-f962-v9hr-pfg5

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