Synapse is an open-source Matrix homeserver written and maintained by the Matrix.org Foundation. The Matrix Federation API allows remote homeservers to request the authorization events in a room. This is necessary so that a homeserver receiving some events can validate that those events are legitimate and permitted in their room. However, in versions of Synapse up to and including 1.68.0, a Synapse homeserver answering a query for authorization events does not sufficiently check that the requesting server should be able to access them. The issue was patched in Synapse 1.69.0. Homeserver administrators are advised to upgrade.
cpe:2.3:a:matrix:synapse:*:*:*:*:*:*:*:*
C52C39A8-CA23-4EFF-ACCC-25C9FD8A83AA
1.69.0
OR
If a remote server sends us a federation request (such as `get_missing_events`, or requesting a space summary) during a state resync, we may well reject that request due to not thinking the remote server is in the room. 

Possibly we need to define some return code to say "sorry, can't auth you right now".

Faster joins: incoming federation requests during resync may be incorrectly rejected
This is a GitHub Issue
repo:synapse
owner:matrix-org
Title : Faster joins: incoming federation requests during resync may be incorrectly rejected
Issue date:

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If a remote server sends us a federation request (such as `get_missing_events`, or requesting a space summary) during a state resync, we may well reject that request due to not thinking the remote server is in the room. 

Possibly we need to define some return code to say "sorry, can't auth you right now".

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comments :
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