{"id":"CVE-2022-39246","state":"PUBLISHED","title":"matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions","description":"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)`.","publishedAt":"2022-09-28T20:00:19.000Z","updatedAt":"2025-04-23T16:54:47.328Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["matrix-org matrix-android-sdk2"],"affected":[{"vendor":"matrix-org","product":"matrix-android-sdk2","versions":[{"version":"< 1.5.1","status":"affected"}]}],"references":["https://github.com/matrix-org/matrix-spec-proposals/pull/3061","https://github.com/matrix-org/matrix-android-sdk2/security/advisories/GHSA-2pvj-p485-cp3m","https://github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f7a4740a17e","https://github.com/matrix-org/matrix-android-sdk2/releases/tag/v1.5.1"],"weaknesses":["CWE-322","CWE-287"],"ingestedAt":"2026-10-29T19:50:29.496Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2022/39xxx/CVE-2022-39246.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2022-39246","state":"PUBLISHED","datePublished":"2022-09-28T20:00:19.000Z","dateUpdated":"2025-04-23T16:54:47.328Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2022-09-02T00:00:00.000Z"},"containers":{"cna":{"title":"matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions","descriptions":[{"lang":"en","value":"matrix-android-sdk2 is the Matrix SDK for Android. 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