matrix-react-sdk is react-based software development kit for inserting a Matrix chat/VOIP client into a web page. Starting in version 3.18.0 and before 3.102.0, matrix-react-sdk allows a malicious homeserver to potentially steal message keys for a room when a user invites another user to that room, via injection of a malicious device controlled by the homeserver. This is possible because matrix-react-sdk before 3.102.0 shared historical message keys on invite. Version 3.102.0 fixes this issue by disabling sharing message keys on invite by removing calls to the vulnerable functionality. No known workarounds are available.
Malicious homeservers can steal message keys when the matrix-react-sdk user invites another user to a room