Cross-site Scripting (XSS) in jupyter/nbconvert_CVE-2026-6658

{
    "lastseen": "",
    "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.",
    "published": "2026-06-26T09:40:30.952Z",
    "modified": "2026-06-26T10:19:12.444Z",
    "type": "cve",
    "title": "Cross-site Scripting (XSS) in jupyter/nbconvert",
    "source": "@huntr_ai",
    "references": "https://huntr.com/bounties/47570290-3b26-4477-8cfa-fdef7db5aefe",
    "id": "CVE-2026-6658",
    "bulletinFamily": "",
    "cwe": [
        "CWE-79"
    ],
    "cvelist": null,
    "sourceData": "jupyter jupyter/jupyter unspecified",
    "sourceHref": "",
    "cvss": {
        "score": 5.4,
        "severity": "MEDIUM",
        "vector": "CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
        "version": "3.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "jupyter/jupyter",
    "version": "unspecified",
    "vendor": "jupyter",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}