matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions

{
  "id": "b4d26a48fb11fefd040926979d5b7f70e624ebeee629cc0262307165bb007513",
  "url": "https://osv.dev/vulnerability/CVE-2022-39246",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions",
    "summary": "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)`.",
    "evidence": "osv:CVE-2022-39246",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2022-39246",
      "aliases": [
        "CVE-2022-39246",
        "GHSA-2pvj-p485-cp3m"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/matrix-org/matrix-android-sdk2",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "e1b2844afce399811162b1015c0d4740e6d9de9a"
                },
                {
                  "fixed": "77df720a238d17308deab83ecaa37f7a4740a17e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.5.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "77df720a238d17308deab83ecaa37f7a4740a17e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e1b2844afce399811162b1015c0d4740e6d9de9a"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.5.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.4.36",
            "v1.4.34",
            "v1.4.32",
            "v1.4.27",
            "v1.4.25",
            "v1.4.16",
            "v1.4.14",
            "v1.4.13",
            "v1.4.11",
            "v1.4.2",
            "v1.3.18",
            "v1.3.14",
            "v1.3.13",
            "v1.3.10",
            "v1.3.9",
            "v1.3.8",
            "v1.3.7",
            "v1.3.4",
            "v1.3.2",
            "v1.3.0",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0-RC3",
            "v1.2.0-RC2",
            "v1.2.0",
            "v1.2.0-RC1",
            "v1.1.9",
            "v1.1.8",
            "v1.1.5",
            "v1.1.4",
            "v1.1.1",
            "v1.0.16",
            "v1.0.13",
            "v1.0.12",
            "v1.0.11",
            "v1.0.10",
            "v1.0.9",
            "v1.0.7",
            "v1.0.6",
            "v1.0.5",
            "v0.0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-39246.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:36.778404645Z",
      "provider": "osv",
      "references": [
        "https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.5.1",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39246.json",
        "https://github.com/matrix-org/matrix-android-sdk2/security/advisories/GHSA-2pvj-p485-cp3m",
        "https://nvd.nist.gov/vuln/detail/CVE-2022-39246",
        "https://github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f7a4740a17e",
        "https://github.com/matrix-org/matrix-spec-proposals/pull/3061"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287",
          "CWE-322"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/39xxx/CVE-2022-39246.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-39246",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504024,
  "published_at": "2022-09-28T20:00:19+00:00"
}