Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.27.0, 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. This is fixed in version 1.27.0.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an     ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.27.0, 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. This is fixed in version 1.27.0. (CVE-2021-21333)

Note that Nessus relies on the presence of the package as reported by the vendor.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - Synapse is a Matrix reference homeserver written in python (pypi package matrix-synapse). Matrix is an
    ecosystem for open federated Instant Messaging and VoIP. In Synapse before version 1.27.0, 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. This is fixed in version 1.27.0. (CVE-2021-21333)

ID	Name	Product	Family	Severity
256653	Linux Distros Unpatched Vulnerability : CVE-2021-21333	Nessus	Misc.	medium
413677	SCA: security update for matrix-synapse (GHSA-c5f8-35qr-q4fm)	Tenable Cloud Security	SCA Checks	medium
413677	SCA: security update for matrix-synapse (GHSA-c5f8-35qr-q4fm)	Tenable Self-Hosted Container Security	SCA Checks	medium

Detections

Analytics

CVE-2021-21333

medium

Tenable Plugins

medium

medium

medium