VDB
CVE-2026-6658
CVE-2026-6658
PUBLISHED
CVSS 5.4 MEDIUM
Reported by @huntr_ai · Published June 26, 2026
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.
Risk Scores
CVSS 3.0
5.4
CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| jupyter | jupyter/jupyter | unspecified |
| jupyter | jupyter/jupyter | unspecified |
Timeline
- Jun 26, 2026 CVE Published
- Jun 26, 2026 CVE Updated
- Jun 27, 2026 EPSS Score
- Jun 27, 2026 Coalition ESS Score
- Jun 29, 2026 Security Advisory
- Aug 24, 2026 EPSS Score
- Sep 5, 2026 EPSS Score
- Sep 12, 2026 EPSS Score
- Sep 18, 2026 EPSS Score