Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and prior, unauthorised users can access the name, avatar, topic and number of members of a room if they know the ID of the room. This vulnerability is limited to homeservers where the vulnerable homeserver is in the room and untrusted users are permitted to create groups (communities). By default, only homeserver administrators can create groups. However, homeserver administrators can already access this information in the database or using the admin API. As a result, only homeservers where the configuration setting `enable_group_creation` has been set to `true` are impacted. Server administrators should upgrade to 1.41.1 or higher to patch the vulnerability. There are two potential workarounds. Server administrators can set `enable_group_creation` to `false` in their homeserver configuration (this is the default value) to prevent creation of groups by non-administrators. Administrators that are using a reverse proxy could, with partial loss of group functionality, block the endpoints `/_matrix/client/r0/groups/{group_id}/rooms` and `/_matrix/client/unstable/groups/{group_id}/rooms`.

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

  - Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and     prior, unauthorised users can access the name, avatar, topic and number of members of a room if they know     the ID of the room. This vulnerability is limited to homeservers where the vulnerable homeserver is in the     room and untrusted users are permitted to create groups (communities). By default, only homeserver     administrators can create groups. However, homeserver administrators can already access this information     in the database or using the admin API. As a result, only homeservers where the configuration setting     `enable_group_creation` has been set to `true` are impacted. Server administrators should upgrade to     1.41.1 or higher to patch the vulnerability. There are two potential workarounds. Server administrators     can set `enable_group_creation` to `false` in their homeserver configuration (this is the default value)     to prevent creation of groups by non-administrators. Administrators that are using a reverse proxy could,     with partial loss of group functionality, block the endpoints `/_matrix/client/r0/groups/{group_id}/rooms`     and `/_matrix/client/unstable/groups/{group_id}/rooms`. (CVE-2021-39163)

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

There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and
    prior, unauthorised users can access the name, avatar, topic and number of members of a room if they know
    the ID of the room. This vulnerability is limited to homeservers where the vulnerable homeserver is in the
    room and untrusted users are permitted to create groups (communities). By default, only homeserver
    administrators can create groups. However, homeserver administrators can already access this information
    in the database or using the admin API. As a result, only homeservers where the configuration setting
    `enable_group_creation` has been set to `true` are impacted. Server administrators should upgrade to
    1.41.1 or higher to patch the vulnerability. There are two potential workarounds. Server administrators
    can set `enable_group_creation` to `false` in their homeserver configuration (this is the default value)
    to prevent creation of groups by non-administrators. Administrators that are using a reverse proxy could,
    with partial loss of group functionality, block the endpoints `/_matrix/client/r0/groups/{group_id}/rooms`
    and `/_matrix/client/unstable/groups/{group_id}/rooms`. (CVE-2021-39163)

  - Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and
    prior, unauthorised users can access the membership (list of members, with their display names) of a room
    if they know the ID of the room. The vulnerability is limited to rooms with `shared` history visibility.
    Furthermore, the unauthorised user must be using an account on a vulnerable homeserver that is in the
    room. Server administrators should upgrade to 1.41.1 or later in order to receive the patch. One
    workaround is available. Administrators of servers that use a reverse proxy could, with potentially
    unacceptable loss of functionality, block the endpoints: `/_matrix/client/r0/rooms/{room_id}/members` with
    `at` query parameter, and `/_matrix/client/unstable/rooms/{room_id}/members` with `at` query parameter.
    (CVE-2021-39164)

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

  - Matrix is an ecosystem for open federated Instant Messaging and Voice over IP. In versions 1.41.0 and
    prior, unauthorised users can access the name, avatar, topic and number of members of a room if they know
    the ID of the room. This vulnerability is limited to homeservers where the vulnerable homeserver is in the
    room and untrusted users are permitted to create groups (communities). By default, only homeserver
    administrators can create groups. However, homeserver administrators can already access this information
    in the database or using the admin API. As a result, only homeservers where the configuration setting
    `enable_group_creation` has been set to `true` are impacted. Server administrators should upgrade to
    1.41.1 or higher to patch the vulnerability. There are two potential workarounds. Server administrators
    can set `enable_group_creation` to `false` in their homeserver configuration (this is the default value)
    to prevent creation of groups by non-administrators. Administrators that are using a reverse proxy could,
    with partial loss of group functionality, block the endpoints `/_matrix/client/r0/groups/{group_id}/rooms`
    and `/_matrix/client/unstable/groups/{group_id}/rooms`. (CVE-2021-39163)

Matrix developers report :

This release patches two moderate severity issues which could reveal metadata about private rooms :

- CVE-2021-39164: Enumerating a private room's list of members and their display names.

- CVE-2021-39163: Disclosing a private room's name, avatar, topic, and number of members.

ID	Name	Product	Family	Severity
255962	Linux Distros Unpatched Vulnerability : CVE-2021-39163	Nessus	Misc.	low
426812	Alpine: multiple synapse packages: security update to 1.41.1-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	low
426812	Alpine: multiple synapse packages: security update to 1.41.1-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	low
416406	SCA: security update for matrix-synapse (GHSA-jj53-8fmw-f2w2)	Tenable Cloud Security	SCA Checks	low
416406	SCA: security update for matrix-synapse (GHSA-jj53-8fmw-f2w2)	Tenable Self-Hosted Container Security	SCA Checks	low
400128	Alpine: multiple synapse packages: security update to 1.41.0-r0 (deprecated)	Tenable Cloud Security	Alpine Linux Local Security Checks	low
400128	Alpine: multiple synapse packages: security update to 1.41.0-r0 (deprecated)	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	low
153074	FreeBSD : py-matrix-synapse -- several vulnerabilities (a67e358c-0bf6-11ec-875e-901b0e9408dc)	Nessus	FreeBSD Local Security Checks	low

Detections

Analytics

CVE-2021-39163

low

Tenable Plugins

low

low

low

low

low

low

low

low