CVE-2021-39163

Published Aug 31, 2021

Last updated a year ago

Overview

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`.
Source
security-advisories@github.com
NVD status
Modified

Risk scores

CVSS 3.1

Type
Primary
Base score
3.1
Impact score
1.4
Exploitability score
1.6
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
Severity
LOW

CVSS 2.0

Type
Primary
Base score
3.5
Impact score
2.9
Exploitability score
6.8
Vector string
AV:N/AC:M/Au:S/C:P/I:N/A:N

Weaknesses

security-advisories@github.com
CWE-200
nvd@nist.gov
CWE-863

Social media

Hype score
Not currently trending

Configurations