| Vulnerability Name: | CVE-2021-39163 (CCN-208440) | ||||||||||||
| Assigned: | 2021-08-31 | ||||||||||||
| Published: | 2021-08-31 | ||||||||||||
| Updated: | 2021-12-21 | ||||||||||||
| 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 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`. | ||||||||||||
| CVSS v3 Severity: | 3.1 Low (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N) 2.7 Low (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C)
2.7 Low (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C)
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| CVSS v2 Severity: | 3.5 Low (CVSS v2 Vector: AV:N/AC:M/Au:S/C:P/I:N/A:N)
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| Vulnerability Type: | CWE-200 | ||||||||||||
| Vulnerability Consequences: | Obtain Information | ||||||||||||
| References: | Source: MITRE Type: CNA CVE-2021-39163 Source: XF Type: UNKNOWN matrix-cve202139163-info-disc(208440) Source: MISC Type: Patch, Third Party Advisory https://github.com/matrix-org/synapse/commit/cb35df940a Source: MISC Type: Release Notes, Third Party Advisory https://github.com/matrix-org/synapse/releases/tag/v1.41.1 Source: CCN Type: Synapse GIT Repository Adding a private/unlisted room to a community exposes room metadata in an unauthorised manner Source: CONFIRM Type: Mitigation, Third Party Advisory https://github.com/matrix-org/synapse/security/advisories/GHSA-jj53-8fmw-f2w2 Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-f12fdca1bf Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-2e8ed15b14 Source: CCN Type: WhiteSource Vulnerability Database CVE-2021-39163 | ||||||||||||
| Vulnerable Configuration: | Configuration 1: Configuration 2: Configuration CCN 1:  Denotes that component is vulnerable | ||||||||||||
| Oval Definitions | |||||||||||||
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