Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

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

Critical 9.3

In plain English

A critical-severity cross-site scripting in jupyterlab-git from jupyterlab. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.3Critical

Exploit odds (30 days)0.5%top 55.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	jupyterlab-git	0.54.0	GHSA-f962-v9hr-pfg5
PyPI	jupyterlab-git	0.54.0	PYSEC-2026-2540
PyPI	jupyterlab-git-core	0.54.0	GHSA-f962-v9hr-pfg5
PyPI	jupyterlab-git-core	0.54.0	PYSEC-2026-2541
npm	@jupyterlab/git	0.54.0	GHSA-f962-v9hr-pfg5

Affected products (as reported)

Vendor	Product	Versions
jupyterlab	jupyterlab-git	>= 0.30.0b3, < 0.54.0

Weakness: CWE-79 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References

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