{"id":"DEBIAN-CVE-2026-6658","details":"A vulnerability in jupyter/nbconvert versions \u003c= 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 `\u003cpre\u003e` 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.","modified":"2026-09-14T17:03:45.911699387Z","published":"2026-06-26T10:16:22.810Z","upstream":["CVE-2026-6658"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-6658"}],"affected":[{"package":{"name":"nbconvert","ecosystem":"Debian:12","purl":"pkg:deb/debian/nbconvert?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.3-3","6.5.3-4","6.5.3-5","7.16.4-1","7.16.4-2","7.16.5-1","7.16.6-1","7.17.0-1","7.17.1-1","7.17.1-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Debian:13","purl":"pkg:deb/debian/nbconvert?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.16.6-1","7.16.6-1+deb13u1","7.17.0-1","7.17.1-1","7.17.1-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Debian:14","purl":"pkg:deb/debian/nbconvert?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.16.6-1","7.17.0-1","7.17.1-1","7.17.1-2"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-6658.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"}]}