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))
-----BEGIN PGP SIGNATURE-----

iQEzBAABCAAdFiEEv27Axt/F4vrTL/8QOSor00I9eP8FAl063sEACgkQOSor00I9
eP/muQf8CiCwW3jkmqTJgtrZuPts1We57rLTnXXdCD1rIEK4e+t/3mKepfFcbFW5
AnzT3L15pzzyVaLc+AQr5rHl5I4u5eShTmLogBRihzBpg9DBHgDYFJjB9tJZ5PS5
ssgU3kgU36O5sydEnoMtV2/jbocy8tHXAM1kR84iGtI6FvTVYn/okdE825siU+G7
WwVbv/F3p7f8RcFdnjP79VJKXRy3bRaFtPRVw7oEIHkud/Tv8YeK95SHtHDSFnF4
o33AJnFLbLp3yh9eqC7QukailqdfkvC/1PA7lMttWYz14OrdFJhfCU86/Dk3/2r9
aAepF4+UU/YgZUCwwvVgrDyvLnO1ag==
=a1Xv
-----END PGP SIGNATURE-----