Cross-Site Scripting (XSS) in jupyterlab-git (CVE-2026-54527)
Summary
Cross-site scripting in jupyterlab-git (CVE-2026-54527). Successful exploitation can lead to full system takeover. Exploitable via POST /api/terminals. Mitigation: upgrade to 0.54.0 or later.
Original description
The description as published by the source.
Overview
Amazon Web Services (AWS) Security has identified a stored cross-site scripting (XSS) issue in the jupyterlab-git JupyterLab extension that can lead to remote code execution (RCE). The issue exists in the PlainTextDiff.ts component, where the createHeader() method passes Git filenames directly to innerHTML without sanitization when rendering diffs for renamed files in commit history. This allows an adversary to craft a filename containing arbitrary HTML/JavaScript that executes when another user views the rename diff in the Git History tab.
The issue can be leveraged through the rename history view in the JupyterLab Git panel. An adversary creates a file with a crafted filename containing a JavaScript payload (e.g., .py), renames the file in a subsequent commit, and pushes to a shared repository. When a victim clones the repository, navigates to the Git History tab, clicks the rename commit, and then clicks the renamed file to view the diff, the unsanitized filename renders via innerHTML, executing arbitrary JavaScript in the victim's browser session. The injected JavaScript reads the xsrf cookie, opens a JupyterLab terminal via POST /api/terminals, connects via WebSocket, and executes arbitrary shell commands — achieving full RCE. An adversary can leverage this to exfiltrate secrets or credentials from the victim's environment.
Scope of impact
We discovered this issue during internal security testing. The issue is present in the default configuration of JupyterL…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-54527 has been found in jupyterlab-git.
Attackers can target a specific entry point like POST /api/terminals over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.0/10.
What to do: upgrade jupyterlab-git to 0.54.0 or later.
If unsure, ask your IT team or search "jupyterlab-git CVE-2026-54527" on the vendor's site.
CVE-2026-54527 (jupyterlab-git) — CWE-79 / CVSS v3 9.0
Attack vector: remote (network-reachable)
Attack surface: POST /api/terminals
Patched: 0.54.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in jupyterlab-git. Attackers reach the vulnerable code path via POST /api/terminals.
Check the vendor advisory for the affected versions of jupyterlab-git. Attack surface: POST /api/terminals.
Severity: Critical (CVSS 9.0/10). Successful exploitation can lead to full system takeover.
Update to 0.54.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /api/terminals requests with malformed payloads or SQL meta-characters. Run grep -r 'jupyterlab-git' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'jupyterlab-git' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
jupyterlab-gitを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /api/terminals' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/terminalsへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade jupyterlab-git to 0.54.0ステージング環境で 0.54.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
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4Post-deployment verification verify
Replay attack against POST /api/terminals on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web pypi.org
- web pypi.org