ghsa-x958-rvg6-956w
Vulnerability from github
Published
2025-06-10 20:15
Modified
2025-06-12 21:23
Severity ?
4.9 (Medium) - CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
Summary
matrix-sdk-crypto vulnerable to sender of encrypted events being spoofed by homeserver administrator
Details

Summary

matrix-sdk-crypto since version 0.8.0 up to 0.11.0 does not correctly validate the sender of an encrypted event. Accordingly, a malicious homeserver operator can modify events served to clients, making those events appear to the recipient as if they were sent by another user.

Although the CVSS score is 4.9 (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N), we consider this a High Severity security issue.

Details

The Matrix specification requires that clients ensure that "the event’s sender, room_id, and the recorded session_id match a trusted session". The vulnerable matrix-sdk-crypto versions check that the room_id matches that of the session denoted by session_id, but do not check the sender.

Patches

The issue is resolved by 13c1d20, included in versions 0.11.1 and 0.12.0 of matrix-sdk-crypto.

Workarounds

Since a successful attack requires administrator access to the homeserver, users who trust the administrators of their local homeserver are not affected.

References

  • https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2
Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "crates.io",
        "name": "matrix-sdk-crypto"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.8.0"
            },
            {
              "fixed": "0.11.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-48937"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-06-10T20:15:37Z",
    "nvd_published_at": "2025-06-10T16:15:41Z",
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nmatrix-sdk-crypto since version 0.8.0 up to 0.11.0 does not correctly validate the sender of an encrypted event. Accordingly, a malicious homeserver operator can modify events served to clients, making those events appear to the recipient as if they were sent by another user.\n\nAlthough the CVSS score is 4.9 (AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N), we consider this a High Severity security issue.\n\n### Details\n\nThe Matrix specification [requires](https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2) that clients ensure that \"the event\u2019s `sender`, `room_id`, and the recorded `session_id` match a trusted session\". The vulnerable matrix-sdk-crypto versions check that the `room_id` matches that of the session denoted by `session_id`, but do not check the `sender`.\n\n### Patches\n\nThe issue is resolved by [13c1d20](https://github.com/matrix-org/matrix-rust-sdk/commit/13c1d2048286bbabf5e7bc6b015aafee98f04d55), included in versions 0.11.1 and 0.12.0 of matrix-sdk-crypto.\n\n### Workarounds\n\nSince a successful attack requires administrator access to the homeserver, users who trust the administrators of their local homeserver are not affected.\n\n### References\n\n * https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2",
  "id": "GHSA-x958-rvg6-956w",
  "modified": "2025-06-12T21:23:37Z",
  "published": "2025-06-10T20:15:37Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-rust-sdk/security/advisories/GHSA-x958-rvg6-956w"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-48937"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-rust-sdk/commit/13c1d2048286bbabf5e7bc6b015aafee98f04d55"
    },
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-rust-sdk/commit/56980745b4f27f7dc72ac296e6aa003e5d92a75b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/matrix-org/matrix-rust-sdk"
    },
    {
      "type": "WEB",
      "url": "https://rustsec.org/advisories/RUSTSEC-2025-0041.html"
    },
    {
      "type": "WEB",
      "url": "https://spec.matrix.org/v1.14/client-server-api/#mmegolmv1aes-sha2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "matrix-sdk-crypto vulnerable to sender of encrypted events being spoofed by homeserver administrator"
}


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