# CVE-2026-102831: JupyterLab: Cross-site scripting (XSS) in JupyterLab via notebook cells pasted from the system clipboard > Attackers can execute arbitrary scripts in JupyterLab by pasting malicious cells, bypassing output sanitization when specific clipboard settings are enabled. - **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** A user has to click or open something - **Fix available:** Yes - **Published:** 29 Sep 2026 - **Updated:** 2 Oct 2026 - **Also known as:** DEBIAN-CVE-2026-102831, GHSA-6966-vjj6-99xv, MINI-j59r-mhxf-xhgf, MINI-xc4q-827x-rjx8, PYSEC-2026-4057, PYSEC-2026-4058, PYSEC-2026-4060, PYSEC-2026-4112, UBUNTU-CVE-2026-102831 ## What is CVE-2026-102831? CVE-2026-102831 is a high-severity cross-site scripting vulnerability in jupyterlab, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. ### Official description JupyterLab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. From JupyterLab 4.5.0 until 4.5.11 and 4.6.4, from Notebook 7.5.0 until 7.6.3, and from JupyterLite Core 0.7.0 until 0.8.4, the system clipboard cell-paste path accepts attacker-controlled cell JSON without clearing metadata.trusted. When useSystemClipboardForCells is active and pasteCodeCellsWithoutOutput is disabled, a pasted code cell can mark HTML output as trusted, bypass output sanitization, and execute script in the authenticated JupyterLab origin without executing the cell. Markdown and raw cells are not affected because their output is sanitized. This issue is fixed in JupyterLab 4.5.11 and 4.6.4, Notebook 7.6.3, and JupyterLite Core 0.8.4. Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-345 (Insufficient Verification of Data Authenticity) ## Which versions are affected by CVE-2026-102831? 14 open source packages ship an affected version, including jupyterlab, jupyterlite and jupyterlite-core. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `jupyterlab` | PyPI | From 4.5.0 | 4.5.11, 4.6.4 | | `jupyterlab` | PyPI | From 4.5.0 | 4.5.11 | | `jupyterlab` | PyPI | From 4.5.0 | 4.5.11 | | `jupyterlab` | PyPI | From 4.6.0 | 4.6.4 | | `jupyterlab` | PyPI | From 4.6.0 | 4.6.4 | | `jupyterlite` | PyPI | From 0.7.0 | 0.8.4 | | `jupyterlite` | PyPI | From 0.7.0 | 0.8.4 | | `jupyterlite` | PyPI | From 0.7.0 | 0.8.4 | | `jupyterlite-core` | PyPI | From 0.7.0 | 0.8.4 | | `jupyterlite-core` | PyPI | From 0.7.0 | 0.8.4 | | `jupyterlite-core` | PyPI | From 0.7.0 | 0.8.4 | | `notebook` | PyPI | From 7.5.0 | 7.6.3 | | `notebook` | PyPI | From 7.5.0 | 7.6.3 | | `notebook` | PyPI | From 7.5.0 | 7.6.3 | ## How do I fix CVE-2026-102831? Upgrade jupyterlab to a fixed version for your release line: 4.5.11 or 4.6.4. ## Is CVE-2026-102831 being exploited? There is no known exploitation of CVE-2026-102831 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-102831 and fix it if it is affected. What it is: CVE-2026-102831 is a high-severity cross-site scripting vulnerability in jupyterlab, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link. Exploitation: There is no known exploitation of CVE-2026-102831 in the wild and no public exploit code. Affected packages and fixed versions: - jupyterlab (PyPI): affected from 4.5.0; fixed in 4.5.11, 4.6.4 - jupyterlab (PyPI): affected from 4.5.0; fixed in 4.5.11 - jupyterlab (PyPI): affected from 4.5.0; fixed in 4.5.11 - jupyterlab (PyPI): affected from 4.6.0; fixed in 4.6.4 - jupyterlab (PyPI): affected from 4.6.0; fixed in 4.6.4 - jupyterlite (PyPI): affected from 0.7.0; fixed in 0.8.4 - jupyterlite (PyPI): affected from 0.7.0; fixed in 0.8.4 - jupyterlite (PyPI): affected from 0.7.0; fixed in 0.8.4 - jupyterlite-core (PyPI): affected from 0.7.0; fixed in 0.8.4 - jupyterlite-core (PyPI): affected from 0.7.0; fixed in 0.8.4 - jupyterlite-core (PyPI): affected from 0.7.0; fixed in 0.8.4 - notebook (PyPI): affected from 7.5.0; fixed in 7.6.3 Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-102831/ (Markdown: https://insights.sbomify.com/CVE-2026-102831/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-102831 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-102831 - OSV: https://osv.dev/vulnerability/CVE-2026-102831 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-102831/ Summaries are generated and may contain mistakes; the official description above is the record.