Synapse 1.2.1 (2019-07-26) ========================== Security update --------------- This release includes *four* security fixes: - Prevent an attack where a federated server could send redactions for arbitrary events in v1 and v2 rooms. ([\#5767](https://github.com/matrix-org/synapse/issues/5767)) - Prevent a denial-of-service attack where cycles of redaction events would make Synapse spin infinitely. Thanks to `@lrizika:matrix.org` for identifying and responsibly disclosing this issue. ([0f2ecb961](https://github.com/matrix-org/synapse/commit/0f2ecb961)) - Prevent an attack where users could be joined or parted from public rooms without their consent. Thanks to @dylangerdaly for identifying and responsibly disclosing this issue. ([\#5744](https://github.com/matrix-org/synapse/issues/5744)) - Fix a vulnerability where a federated server could spoof read-receipts from users on other servers. Thanks to @dylangerdaly for identifying this issue too. ([\#5743](https://github.com/matrix-org/synapse/issues/5743)) Additionally, the following fix was in Synapse **1.2.0**, but was not correctly identified during the original release: - It was possible for a room moderator to send a redaction for an `m.room.create` event, which would downgrade the room to version 1. Thanks to `/dev/ponies` for identifying and responsibly disclosing this issue! ([\#5701](https://github.com/matrix-org/synapse/issues/5701))