PatchSiren

PatchSiren cyber security CVE debrief

CVE-2026-54527 jupyterlab CVE debrief

The JupyterLab Git extension for JupyterLab, from version 0.30.0b3 before 0.54.0, contains a vulnerability. The PlainTextDiff.ts createHeader() method passes Git filenames directly to innerHTML when rendering renamed files in commit history. This allows a crafted filename to execute JavaScript when a victim views the rename diff in the Git History tab.

Vendor
jupyterlab
Product
jupyterlab-git
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-08
Original CVE updated
2026-07-10
Advisory published
2026-07-08
Advisory updated
2026-07-10

Who should care

Users of JupyterLab with the Git extension installed, particularly those who view commit history or rename diffs, should be aware of this vulnerability. Administrators and developers using JupyterLab in their projects should prioritize updating to version 0.54.0 or later.

Technical summary

The vulnerability exists in the PlainTextDiff.ts file within the JupyterLab Git extension. Specifically, the createHeader() method does not properly sanitize filenames before rendering them in the Git History tab. This allows an attacker to craft a filename that includes JavaScript code, which will be executed when a user views the rename diff. The issue was fixed in version 0.54.0. Affected product deployments should be reviewed for exposure, and administrators should prioritize updating to version 0.54.0 or later to mitigate this critical vulnerability.

Defensive priority

High priority should be given to updating the JupyterLab Git extension to version 0.54.0 or later. Users should also be cautious when viewing commit history or rename diffs from untrusted sources.

Recommended defensive actions

  • Update JupyterLab Git extension to version 0.54.0 or later
  • Review commit history and rename diffs from untrusted sources with caution
  • Implement Content Security Policy (CSP) to mitigate JavaScript execution risks
  • Monitor for suspicious activity in JupyterLab instances
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
  • Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
  • Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed

Evidence notes

The CVE record was published on 2026-07-08T21:16:49.273Z and last modified on 2026-07-10T19:05:27.310Z. The NVD entry is currently Awaiting Analysis. References include GitHub commits and releases related to the JupyterLab Git extension.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54527 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54527

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54527 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54527

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.