{
  "cveId": "CVE-2026-40934",
  "url": "https://patchblox.com/security/cve/CVE-2026-40934",
  "summary": "CVE-2026-40934 is fixed in jupyter-server on 1 platform by DEBIAN-CVE-2026-40934 (version 2.20.0-1), released May 5, 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. In versions 2.17.0 and earlier, the secret used to sign authentication cookies is persisted to a static file at ~/.local/share/jupyter/runtime/jupyter_cookie_secret and is never rotated when a user changes their password. After a password reset and server restart, any previously issued authentication cookie remains cryptographically valid because the signing key has not changed. An attacker who has captured a session cookie through any means retains full authenticated access to the server regardless of subsequent password changes. This affects deployments using password-based authentication, particularly shared or public-facing servers where credential rotation is expected to revoke existing sessions. This issue has been fixed in version 2.18.0.",
  "published": "2026-05-05T22:16:00Z",
  "severity": "medium",
  "cvss": 6.8,
  "cvssVector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N",
  "epss": 0.00332,
  "epssPercentile": 0.2661,
  "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-2026-40934",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-40934",
      "released": "2026-05-05T22:16:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}