ghsa-35g4-qx3c-vjhx
Vulnerability from github
Published
2021-06-21 17:09
Modified
2021-06-16 20:08
Severity ?
6.5 (Medium) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Summary
Automatic room upgrade handling can be used maliciously to bridge a room non-consentually
Details

Impact

If a bridge has room upgrade handling turned on in the configuration (the roomUpgradeOpts key when instantiating a new Bridge instance.), any m.room.tombstone event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room m.room.create event is not checked to verify if the predecessor field contains the previous room. This means that any mailcious admin of a bridged room can repoint the traffic to a different room without the new room being aware.

Patches

Versions 2.6.1 and greater are patched.

Workarounds

Disabling the automatic room upgrade handling can be done by removing the roomUpgradeOpts key from the Bridge class options.

References

The issue is patched by https://github.com/matrix-org/matrix-appservice-bridge/pull/330

For more information]

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

Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "matrix-appservice-bridge"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.6.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32659"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-306"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-06-16T20:08:37Z",
    "nvd_published_at": "2021-06-16T19:15:00Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nIf a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any mailcious admin of a bridged room can repoint the traffic to a different room without the new room being aware.\n\n\n### Patches\n\nVersions 2.6.1 and greater are patched.\n\n### Workarounds\n\nDisabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options. \n\n### References\n\nThe issue is patched by https://github.com/matrix-org/matrix-appservice-bridge/pull/330\n\n### For more information]\n\nIf you have any questions or comments about this advisory, email us at security@matrix.org.",
  "id": "GHSA-35g4-qx3c-vjhx",
  "modified": "2021-06-16T20:08:37Z",
  "published": "2021-06-21T17:09:22Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/security/advisories/GHSA-35g4-qx3c-vjhx"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32659"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/pull/330"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/commit/b69e745584a34fcfd858df33e4631e420da07b9f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-appservice-bridge/releases/tag/2.6.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Automatic room upgrade handling can be used maliciously to bridge a room non-consentually "
}


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