GHSA-JJ53-8FMW-F2W2

Vulnerability from github – Published: 2021-09-01 18:25 – Updated: 2024-09-24 15:37
VLAI?
Summary
Adding a private/unlisted room to a community exposes room metadata in an unauthorised manner.
Details

Impact

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.

Patches

Server administrators should upgrade to 1.41.1 or higher.

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 following endpoints: * /_matrix/client/r0/groups/{group_id}/rooms * /_matrix/client/unstable/groups/{group_id}/rooms

References

n/a

For more information

If you have any questions or comments about this advisory, e-mail us at security@matrix.org.

Severity ?
3.1 (Low)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
2.3 (Low)
CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.41.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-39163"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-08-31T17:46:08Z",
    "nvd_published_at": "2021-08-31T16:15:00Z",
    "severity": "LOW"
  },
  "details": "### Impact\nUnauthorised 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:\n- the vulnerable homeserver is in the room; and\n- untrusted users are permitted to create groups (communities).\n\nBy 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.\n\n### Patches\nServer administrators should upgrade to 1.41.1 or higher.\n\n### Workarounds\nServer 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.\n\nAdministrators that are using a reverse proxy could, with partial loss of group functionality, block the following endpoints:\n* `/_matrix/client/r0/groups/{group_id}/rooms`\n* `/_matrix/client/unstable/groups/{group_id}/rooms`\n\n### References\nn/a\n\n### For more information\nIf you have any questions or comments about this advisory, e-mail us at security@matrix.org.\n",
  "id": "GHSA-jj53-8fmw-f2w2",
  "modified": "2024-09-24T15:37:56Z",
  "published": "2021-09-01T18:25:44Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-jj53-8fmw-f2w2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-39163"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/commit/cb35df940a"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/synapse"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/releases/tag/v1.41.1"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pypa/advisory-database/tree/main/vulns/matrix-synapse/PYSEC-2021-424.yaml"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VHDEPCZ22GJFMZCWA2XZAGPOEV72POF"
    },
    {
      "type": "WEB",
      "url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PXT7ID7DNBRN2TVTETU3SYQHJKEG6PXN"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Adding a private/unlisted room to a community exposes room metadata in an unauthorised manner."
}


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Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.