{"id":"CVE-2026-6658","state":"PUBLISHED","title":"Cross-site Scripting (XSS) in jupyter/nbconvert","description":"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.","publishedAt":"2026-06-26T09:40:30.952Z","updatedAt":"2026-06-26T10:19:12.444Z","severity":{"score":5.4,"label":"Medium","version":"3.0","vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","source":"@huntr_ai"},"assigner":"@huntr_ai","products":["jupyter jupyter/jupyter"],"affected":[{"vendor":"jupyter","product":"jupyter/jupyter","versions":[{"version":"unspecified","status":"affected","lessThanOrEqual":"latest","versionType":"custom"}]}],"references":["https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe"],"weaknesses":["CWE-79"],"ingestedAt":"2026-10-29T20:12:49.727Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/6xxx/CVE-2026-6658.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-6658","state":"PUBLISHED","datePublished":"2026-06-26T09:40:30.952Z","dateUpdated":"2026-06-26T10:19:12.444Z","assignerShortName":"@huntr_ai","assignerOrgId":"c09c270a-b464-47c1-9133-acb35b22c19a","dateReserved":"2026-04-20T08:17:42.331Z"},"containers":{"cna":{"title":"Cross-site Scripting (XSS) in jupyter/nbconvert","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"jupyter","product":"jupyter/jupyter","versions":[{"version":"unspecified","status":"affected","lessThanOrEqual":"latest","versionType":"custom"}]}],"references":[{"url":"https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe"}],"metrics":[{"cvssV3_0":{"version":"3.0","attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"LOW","scope":"CHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","baseScore":5.4,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-79","type":"CWE","lang":"en","description":"CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')"}]}],"providerMetadata":{"shortName":"@huntr_ai","orgId":"c09c270a-b464-47c1-9133-acb35b22c19a","dateUpdated":"2026-06-26T09:40:30.952Z"},"source":{"advisory":"47570290-3b26-4477-8cfa-fdef7db5aefe","discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-26T10:19:03.505659Z","id":"CVE-2026-6658","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-26T10:19:12.444Z"}}]}}}