{"id":"UBUNTU-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":"2026-06-29T23:19:16.925317999Z","published":"2026-06-26T10:16:00Z","upstream":["CVE-2026-6658"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-6658"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-6658"},{"type":"REPORT","url":"https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe"},{"type":"REPORT","url":"https://github.com/jupyter/nbconvert/pull/1957"}],"affected":[{"package":{"name":"nbconvert","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.2.0-4","5.3.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-nbconvert","binary_version":"5.3.1-1"},{"binary_version":"5.3.1-1","binary_name":"python-nbconvert"},{"binary_name":"python3-nbconvert","binary_version":"5.3.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.4-2ubuntu2","5.6.0-1","5.6.0-2","5.6.1-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-nbconvert","binary_version":"5.6.1-1"},{"binary_name":"python3-nbconvert","binary_version":"5.6.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.6.1-3","6.1.0-1","6.3.0-1","6.4.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"6.4.0-1","binary_name":"jupyter-nbconvert"},{"binary_version":"6.4.0-1","binary_name":"python3-nbconvert"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.3-4","6.5.3-5"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-nbconvert","binary_version":"6.5.3-5"},{"binary_name":"python3-nbconvert","binary_version":"6.5.3-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.16.6-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-nbconvert","binary_version":"7.16.6-1"},{"binary_name":"python3-nbconvert","binary_version":"7.16.6-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}},{"package":{"name":"nbconvert","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/nbconvert?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["7.16.6-1","7.17.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-nbconvert","binary_version":"7.17.0-1"},{"binary_version":"7.17.0-1","binary_name":"python3-nbconvert"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-6658.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}