GHSA-3X4C-PQ33-4W3Q

Vulnerability from github – Published: 2021-09-01 18:25 – Updated: 2024-09-24 15:36
VLAI?
Summary
Improper authorisation of members discloses room membership to non-members
Details

Impact

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.

Patches

Server administrators should upgrade to 1.41.1 or later.

Workarounds

Administrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the following endpoints: * /_matrix/client/r0/rooms/{room_id}/members with at query parameter * /_matrix/client/unstable/rooms/{room_id}/members with at query parameter

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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "matrix-synapse"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.41.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-39164"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-08-31T19:13:32Z",
    "nvd_published_at": "2021-08-31T17:15:00Z",
    "severity": "LOW"
  },
  "details": "### Impact\nUnauthorised 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.\n\n### Patches\nServer administrators should upgrade to 1.41.1 or later.\n\n### Workarounds\nAdministrators of servers that use a reverse proxy could, with potentially unacceptable loss of functionality, block the following endpoints:\n* `/_matrix/client/r0/rooms/{room_id}/members` with `at` query parameter\n* `/_matrix/client/unstable/rooms/{room_id}/members` with `at` query parameter\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.",
  "id": "GHSA-3x4c-pq33-4w3q",
  "modified": "2024-09-24T15:36:22Z",
  "published": "2021-09-01T18:25:27Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/synapse/security/advisories/GHSA-3x4c-pq33-4w3q"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-39164"
    },
    {
      "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-2021-425.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"
    }
  ],
  "summary": "Improper authorisation of members discloses room membership to non-members"
}


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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.



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