{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "77df720a238d17308deab83ecaa37f7a4740a17e"
            }
          ],
          "repo": "https://github.com/matrix-org/matrix-android-sdk2",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "e1b2844afce399811162b1015c0d4740e6d9de9a"
            }
          ],
          "repo": "https://github.com/matrix-org/matrix-android-sdk2",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "77df720a238d17308deab83ecaa37f7a4740a17e"
            }
          ],
          "repo": "https://github.com/matrix-org/matrix-android-sdk2",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "e1b2844afce399811162b1015c0d4740e6d9de9a"
            }
          ],
          "repo": "https://github.com/matrix-org/matrix-android-sdk2",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-2pvj-p485-cp3m"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-287",
      "CWE-322"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39246.json"
  },
  "details": "matrix-android-sdk2 is the Matrix SDK for Android. Prior to version 1.5.1, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the key forwarding strategy implemented in the matrix-android-sdk2 that is too permissive. Starting with version 1.5.1, the default policy for accepting key forwards has been made more strict in the matrix-android-sdk2. The matrix-android-sdk2 will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately (for example, by showing a warning for such messages). As a workaroubnd, current users of the SDK can disable key forwarding in their forks using `CryptoService#enableKeyGossiping(enable: Boolean)`.",
  "id": "CVE-2022-39246",
  "modified": "2026-04-01T23:08:06.593017108Z",
  "published": "2022-09-28T20:00:19Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.5.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39246.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/matrix-org/matrix-android-sdk2/security/advisories/GHSA-2pvj-p485-cp3m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-39246"
    },
    {
      "type": "FIX",
      "url": "https://github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f7a4740a17e"
    },
    {
      "type": "FIX",
      "url": "https://github.com/matrix-org/matrix-spec-proposals/pull/3061"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions"
}