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)`.
History

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2022-09-28T20:00:19

Updated: 2024-08-03T12:00:43.348Z

Reserved: 2022-09-02T00:00:00

Link: CVE-2022-39246

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2022-09-28T20:15:14.160

Modified: 2024-11-21T07:17:52.157

Link: CVE-2022-39246

cve-icon Redhat

No data.