Vulnerability Monitor

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CVE-2021-39164

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.

Published

2021-08-31T17:15:08.267

Last Modified

2024-11-21T06:18:45.903

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 3.1 (LOW)

CVSSv2 Vector

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

  • Access Vector: NETWORK
  • Access Complexity: MEDIUM
  • Authentication: SINGLE
  • Confidentiality Impact: PARTIAL
  • Integrity Impact: NONE
  • Availability Impact: NONE
Exploitability Score

6.8

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-200
  • Type: Primary
    CWE-863
Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application matrix synapse < 1.41.1 Yes
Operating System fedoraproject fedora 34 Yes
Operating System fedoraproject fedora 35 Yes
References