CVE-2026-6658
Cross-site Scripting (XSS) in jupyter/nbconvert
CVSS Score
5.4
EPSS Score
0.0%
EPSS Percentile
0th
A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized `text/vnd.mermaid` output in HTML exports. The `data_mermaid` block in `share/templates/lab/base.html.j2` renders `text/vnd.mermaid` cell output directly into HTML without escaping, enabling attackers to inject arbitrary HTML/JavaScript by breaking out of the `<pre>` tag. This vulnerability impacts any server using nbconvert to render notebooks as HTML, allowing attackers to execute arbitrary JavaScript in the context of users viewing the HTML export.
| CWE | CWE-79 |
| Vendor | jupyter |
| Product | jupyter/jupyter |
| Published | Jun 26, 2026 |
| Last Updated | Jun 26, 2026 |
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CVSS v3 Breakdown
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Affected Versions
jupyter / jupyter/jupyter
unspecified ≤ latest