CVE-2021-39163

low
New! CVE Severity Now Using CVSS v3

The calculated severity for CVEs has been updated to use CVSS v3 by default. CVEs that do not have a CVSS v3 score will fall back CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.

Description

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`.

References

https://github.com/matrix-org/synapse/security/advisories/GHSA-jj53-8fmw-f2w2

https://github.com/matrix-org/synapse/releases/tag/v1.41.1

https://github.com/matrix-org/synapse/commit/cb35df940a

https://lists.fedoraproject.org/archives/list/[email protected]/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN/

https://lists.fedoraproject.org/archives/list/[email protected]/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF/

Details

Source: MITRE

Published: 2021-08-31

Updated: 2021-09-24

Type: CWE-200

Risk Information

CVSS v2

Base Score: 3.5

Vector: AV:N/AC:M/Au:S/C:P/I:N/A:N

Impact Score: 2.9

Exploitability Score: 6.8

Severity: LOW

CVSS v3

Base Score: 3.1

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

Impact Score: 1.4

Exploitability Score: 1.6

Severity: LOW

Tenable Plugins

View all (1 total)

IDNameProductFamilySeverity
153074FreeBSD : py-matrix-synapse -- several vulnerabilities (a67e358c-0bf6-11ec-875e-901b0e9408dc)NessusFreeBSD Local Security Checks
low