{"id":"CVE-2022-39246","aliases":["GHSA-2pvj-p485-cp3m"],"url":"https://o3.security/vulnerability/CVE-2022-39246","summary":"matrix-android-sdk2 vulnerable to impersonation via forwarded Megolm sessions","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)`.","published":"2022-09-28T20:00:19Z","modified":"2026-07-15T01:49:01.975807871Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"org.matrix.android:matrix-android-sdk2","fixedVersion":"1.5.1"}],"fix":{"url":"https://github.com/matrix-org/matrix-android-sdk2/commit/77df720a238d17308deab83ecaa37f7a4740a17e","label":"matrix-org/matrix-android-sdk2@77df720"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T01:49:01.975807871Z"}}