QID 981370

QID 981370: Python (pip) Security Update for matrix-synapse (GHSA-c5f8-35qr-q4fm)

Security update has been released for matrix-synapse to fix the vulnerability.

Note: The preceding description block is extracted directly from the security advisory. Using automation, we have attempted to clean and format it as much as possible without introducing additional issues.

The notification emails sent for notifications for missed messages or for an expiring account are subject to HTML injection. In the case of the notification for missed messages, this could allow an attacker to insert forged content into the email.

The account expiry feature is not enabled by default and the HTML injection is not controllable by an attacker.

  • CVSS V3 rated as High - 6.1 severity.
  • CVSS V2 rated as Low - 2.6 severity.
    • Solution
    This issue is fixed in #9200.Workaround:
    For the missed messages notifications:

    The `notif.html`, `notif_mail.html`, and `room.html` templates can be overridden with custom templates that manually escapes the variables using [JInja2's `escape` filter](https://jinja.palletsprojects.com/en/2.11.x/templates/#escape). See the `email.template_dir` setting.

    For the account expiry notifications:

    1. Account expiry can be disabled via the `account_validity.enabled` setting.

    2. The `notice_expiry.html` template can be overridden with a custom template that manually escapes the variables using [JInja2's `escape` filter](https://jinja.palletsprojects.com/en/2.11.x/templates/#escape). See the `email.template_dir` setting.
    Vendor References

    CVEs related to QID 981370

    CVE-2021-21333 |
    Software Advisories
    Advisory ID Software Component Link
    GHSA-c5f8-35qr-q4fm matrix-synapse URL Logo github.com/advisories/GHSA-c5f8-35qr-q4fm
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