CVE-2021-39164

Summary

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.

Affected Software

VendorProductVersion RangeStatus
matrix-orgsynapse< 1.41.1affected

Weaknesses

  • CWE-200: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

ADP Enrichment

CVE Program Container

Additional References

References