{
  "cveId": "CVE-2026-44727",
  "url": "https://patchblox.com/security/cve/CVE-2026-44727",
  "summary": "CVE-2026-44727 is fixed in 4 products on 1 platform, first by FEDORA-2026-275D2ECBBD, released June 26, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "jupyter-server: Jupyter Server is the backend for Jupyter web applications",
  "description": "Jupyter Server is the backend for Jupyter web applications. Prior to 2.20, the nbconvert HTTP handlers in jupyter_server render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their Content-Security-Policy. Combined with nbconvert.HTMLExporter\u0027s default non-sanitizing behavior, a notebook carrying an HTML payload in a display_data output triggers stored XSS with cookie access, full /api/* authority, and kernel RCE. This vulnerability is fixed in 2.20.",
  "published": "2026-06-22T21:16:24Z",
  "severity": "medium",
  "cvss": 5.4,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
  "epss": 0.00438,
  "epssPercentile": 0.38319,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "jupyter-server",
      "release": "Debian 14",
      "fixedVersion": "2.20.0-1",
      "fix": "DEBIAN-CVE-2026-44727",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-44727",
      "released": "2026-07-18T12:42:52Z"
    },
    {
      "platform": "linux",
      "product": "python-jupyter-server",
      "release": "Fedora 43",
      "fixedVersion": "2.20.0-1.fc43",
      "fix": "FEDORA-2026-275D2ECBBD",
      "url": "https://patchblox.com/security/fix/linux/fedora-2026-275d2ecbbd",
      "released": "2026-06-26T16:35:11Z"
    },
    {
      "platform": "linux",
      "product": "python3-jupyter-server",
      "release": "Fedora 43",
      "fixedVersion": "2.20.0-1.fc43",
      "fix": "FEDORA-2026-275D2ECBBD",
      "url": "https://patchblox.com/security/fix/linux/fedora-2026-275d2ecbbd",
      "released": "2026-06-26T16:35:11Z"
    },
    {
      "platform": "linux",
      "product": "python3-jupyter-server\u002Btest",
      "release": "Fedora 43",
      "fixedVersion": "2.20.0-1.fc43",
      "fix": "FEDORA-2026-275D2ECBBD",
      "url": "https://patchblox.com/security/fix/linux/fedora-2026-275d2ecbbd",
      "released": "2026-06-26T16:35:11Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T13:06:02Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}