Information Exposure Affecting matrix-synapse package, versions *
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Test your applications- Snyk ID SNYK-UBUNTU2004-MATRIXSYNAPSE-1582766
- published 4 Sep 2021
- disclosed 31 Aug 2021
Introduced: 31 Aug 2021
CVE-2021-39163 Open this link in a new tabHow to fix?
There is no fixed version for Ubuntu:20.04 matrix-synapse.
NVD Description
Note: Versions mentioned in the description apply only to the upstream matrix-synapse package and not the matrix-synapse package as distributed by Ubuntu.
See How to fix? for Ubuntu:20.04 relevant fixed versions and status.
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
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2021-39163
- https://github.com/matrix-org/synapse/security/advisories/GHSA-jj53-8fmw-f2w2
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN/
- https://github.com/matrix-org/synapse/commit/cb35df940a
- https://github.com/matrix-org/synapse/releases/tag/v1.41.1
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN/