CVE Feed

    Dashboard / CVE / CVE-2026-44727

    CVE-2026-44727

    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's 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:Jun 22, 2026
    Last Modified:Aug 28, 2026
    EPS:Jun 22, 2026
    EPSS Score:0.00438
    CVSS Score:5.4

    Affected Products

    Vendor
    Jupyter
    Product
    Jupyter Server

    Exploits

    No exploit reference

    Related CVEs

    CVE-2026-6658 (CVSS 5.4) — A vulnerability in jupyter/nbconvert versions <= 7.17.0 allows for Cross-site Scripting (XSS) via unsanitized …
    CVE-2026-6657 (CVSS 8.8) — A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin vali…
    CVE-2026-5422 (CVSS 8.1) — A path traversal vulnerability exists in jupyter-server version 2.17.0 due to an incorrect root directory boun…
    CVE-2026-40934 (CVSS 7.6) — Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the secret used to…
    CVE-2026-40110 (CVSS 7.6) — Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the Origin header …
    CVE-2026-35397 (CVSS 7.6) — Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, a path traversal v…
    CVE-2025-61669 (CVSS 6.3) — Jupyter Server is the backend for Jupyter web applications. In jupyter_server versions through 2.17.0, the nex…
    CVE-2024-35178 (CVSS 7.5) — The Jupyter Server provides the backend for Jupyter web applications. Jupyter Server on Windows has a vulnerab…
    CVE-2023-49080 (CVSS 3.5) — The Jupyter Server provides the backend (i.e. the core services, APIs, and REST endpoints) for Jupyter web app…
    CVE-2023-39968 (CVSS 4.3) — jupyter-server is the backend for Jupyter web applications. Open Redirect Vulnerability. Maliciously crafted l…

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High