The GitHub Security Lab discovered sixteen ways to exploit a cross-site scripting vulnerability in nbconvert. When using nbconvert to generate an HTML version of a user-controllable notebook, it is possible to inject arbitrary HTML which may lead to cross-site scripting (XSS) vulnerabilities if these HTML notebooks are served by a web server (eg: nbviewer).

The remote Fedora 38 host has packages installed that are affected by a vulnerability as referenced in the FEDORA-2022-b910e3473f advisory.

    New versions of nbclient and nbconvert.

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Debian 11 host has packages installed that are affected by a vulnerability as referenced in the dla-3863 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-3863-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                       Guilhem Moulin     September 02, 2024                            https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : nbconvert     Version        : 5.6.1-3+deb11u1     CVE ID         : CVE-2021-32862

    Alvaro Muoz from the GitHub Security Lab discovered sixteen ways to     exploit a cross-site scripting vulnerability in nbconvert, a tool and     library used to convert notebooks to various other formats via Jinja     templates.

    When using nbconvert to generate an HTML version of a user-controllable     notebook, it is possible to inject arbitrary HTML which may lead to     cross-site scripting (XSS) vulnerabilities if these HTML notebooks are     served by a web server without tight Content-Security-Policy (e.g.,     nbviewer).

      * GHSL-2021-1013: XSS in notebook.metadata.language_info.pygments_lexer;
      * GHSL-2021-1014: XSS in notebook.metadata.title;
      * GHSL-2021-1015: XSS in notebook.metadata.widgets;
      * GHSL-2021-1016: XSS in notebook.cell.metadata.tags;
      * GHSL-2021-1017: XSS in output data text/html cells;
      * GHSL-2021-1018: XSS in output data image/svg+xml cells;
      * GHSL-2021-1019: XSS in notebook.cell.output.svg_filename;
      * GHSL-2021-1020: XSS in output data text/markdown cells;
      * GHSL-2021-1021: XSS in output data application/javascript cells;
      * GHSL-2021-1022: XSS in output.metadata.filenames image/png and         image/jpeg;
      * GHSL-2021-1023: XSS in output data image/png and image/jpeg cells;
      * GHSL-2021-1024: XSS in output.metadata.width/height image/png and         image/jpeg;
      * GHSL-2021-1025: XSS in output data application/vnd.jupyter.widget-state+         json cells;
      * GHSL-2021-1026: XSS in output data application/vnd.jupyter.widget-view+         json cells;
      * GHSL-2021-1027: XSS in raw cells; and
      * GHSL-2021-1028: XSS in markdown cells.

    Some of these vulnerabilities, namely GHSL-2021-1017, -1020, -1021, and
    -1028, are actually design decisions where text/html, text/markdown,     application/JavaScript and markdown cells should allow for arbitrary     JavaScript code execution.  These vulnerabilities are therefore left open     by default, but users can now opt-out and strip down all JavaScript     elements via a new HTMLExporter option `sanitize_html`.

    For Debian 11 bullseye, this problem has been fixed in version     5.6.1-3+deb11u1.

    We recommend that you upgrade your nbconvert packages.

    For the detailed security status of nbconvert please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/nbconvert

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: PGP signature

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Debian 10 host has packages installed that are affected by a vulnerability as referenced in the dla-3442 advisory.

  - The GitHub Security Lab discovered sixteen ways to exploit a cross-site scripting vulnerability in     nbconvert. When using nbconvert to generate an HTML version of a user-controllable notebook, it is     possible to inject arbitrary HTML which may lead to cross-site scripting (XSS) vulnerabilities if these     HTML notebooks are served by a web server (eg: nbviewer). (CVE-2021-32862)

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
211067	Fedora 38 : python-nbclient / python-nbconvert (2022-b910e3473f)	Nessus	Fedora Local Security Checks	medium
206424	Debian dla-3863 : jupyter-nbconvert - security update	Nessus	Debian Local Security Checks	medium
176658	Debian DLA-3442-1 : nbconvert - LTS security update	Nessus	Debian Local Security Checks	medium

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