CVE-2021-39163

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Summary

CVECVE-2021-39163
StatePUBLIC
Assigner[email protected]
Source PriorityCVE Program / NVD first with legacy fallback
Published2021-08-31 16:15:00 UTC
Updated2023-11-07 03:37:00 UTC
DescriptionMatrix 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`.

Risk And Classification

Problem Types: CWE-200

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Fedoraproject Fedora 34 All All All
Operating System Fedoraproject Fedora 35 All All All
Application Matrix Synapse All All All All

References

ReferenceSourceLinkTags
[SECURITY] Fedora 34 Update: matrix-synapse-1.41.1-1.fc34 - package-announce - Fedora Mailing-Lists FEDORA lists.fedoraproject.org
Adding a private/unlisted room to a community exposes room metadata in an unauthorised manner. · Advisory · matrix-org/synapse · GitHub CONFIRM github.com
[SECURITY] Fedora 35 Update: matrix-synapse-1.41.1-1.fc35 - package-announce - Fedora Mailing-Lists lists.fedoraproject.org
Merge pull request from GHSA-jj53-8fmw-f2w2 · matrix-org/synapse@cb35df9 · GitHub MISC github.com
Release v1.41.1 · matrix-org/synapse · GitHub MISC github.com
FEDORA-2021-f12fdca1bf FEDORA lists.fedoraproject.org
[SECURITY] Fedora 34 Update: matrix-synapse-1.41.1-1.fc34 - package-announce - Fedora Mailing-Lists lists.fedoraproject.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 281885 Fedora Security Update for matrix (FEDORA-2021-2e8ed15b14)
  • 501927 Alpine Linux Security Update for synapse
  • 690046 Free Berkeley Software Distribution (FreeBSD) Security Update for py-matrix-synapse (a67e358c-0bf6-11ec-875e-901b0e9408dc)
  • 980490 Python (pip) Security Update for matrix-synapse (GHSA-jj53-8fmw-f2w2)
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