Cross-Site Scripting (XSS) in jupyterlab (CVE-2026-102831)
Summary
Cross-site scripting in jupyterlab (CVE-2026-102831). Confidential information can be exposed externally. Exploitable via metadata.trusted. Mitigation: upgrade to 4.5.11 or later.
Original description
The description as published by the source.
Description
JupyterLab 4.5.0 enabled copying and pasing cells through the system clipboard. The paste path parses clipboard text as cell JSON and inserts the cells without clearing metadata.trusted, so a payload can declare its own output as trusted. JupyterLab does not sanitize a trusted output and evaluates the `` elements it contains, so pasting the cell runs attacker's JavaScript in the JupyterLab origin. The same payload with "trusted": false is sanitized.
[
{
"cell_type": "code",
"execution_count": null,
"source": "",
"metadata": { "trusted": true },
"outputs": [
{
"output_type": "display_data",
"metadata": {},
"data": { "text/html": "/* runs on paste */" }
}
]
}
]
Users are affected if all of the following are true:
- they run JupyterLab 4.5.0 through 4.6.3, or an application that bundles it such as Notebook 7.5+;
- if running 4.5.2 or newer,
useSystemClipboardForCellsis enabled - it is off by default in 4.5.2+, and always enabled on 4.5.0 and 4.5.1 with no opt-out - they run a Paste Cells command (e.g. from context menu, command palette, shortcut) while attacker-controlled text is in the clipboard; and
pasteCodeCellsWithoutOutputis off, the default, so the pasted cell keeps its outputs
Impact
The script runs in the JupyterLab page, in the same origin and session as the authenticated user, so it can call the Jupyter Server REST API as that user: read and write any file…
Source: NIST National Vulnerability Database 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-2026-102831 has been found in jupyterlab.
Attackers can target a specific entry point like metadata.trusted over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 8.1/10.
What to do: upgrade jupyterlab to 4.5.11 or later.
If unsure, ask your IT team or search "jupyterlab CVE-2026-102831" on the vendor's site.
CVE-2026-102831 (jupyterlab) — CWE-79 / CVSS v3 8.1
Attack vector: remote (network-reachable) / unauthenticated
Attack surface: metadata.trusted / useSystemClipboardForCells / pasteCodeCellsWithoutOutput / jupyterlab
Patched: 4.5.11 — 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. Attackers reach the vulnerable code path via metadata.trusted without authentication.
Check the vendor advisory for the affected versions of jupyterlab. Attack surface: metadata.trusted / useSystemClipboardForCells / pasteCodeCellsWithoutOutput / jupyterlab.
Severity: High (CVSS 8.1/10). Confidential information can be exposed externally.
Update to 4.5.11.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'jupyterlab' . 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
-
1Identify exposure identify
grep -r 'jupyterlab' . | 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を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade jupyterlab to 4.5.11ステージング環境で 4.5.11 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を含めること。
-
3Post-deployment verification verify
Confirm patched version is live in production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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-102831 jupyter-notebook
References
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- package pypi.org
- package pypi.org
- package pypi.org
- package pypi.org
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com