First published: Wed Jun 16 2021(Updated: )
Matrix-appservice-bridge is the bridging service for the Matrix communication program's application services. In versions 2.6.0 and earlier, if a bridge has room upgrade handling turned on in the configuration (the `roomUpgradeOpts` key when instantiating a new `Bridge` instance.), any `m.room.tombstone` event it encounters will be used to unbridge the current room and bridge into the target room. However, the target room `m.room.create` event is not checked to verify if the `predecessor` field contains the previous room. This means that any malicious admin of a bridged room can repoint the traffic to a different room without the new room being aware. Versions 2.6.1 and greater are patched. As a workaround, disabling the automatic room upgrade handling can be done by removing the `roomUpgradeOpts` key from the `Bridge` class options.
Credit: security-advisories@github.com
Affected Software | Affected Version | How to fix |
---|---|---|
Matrix Matrix-appservice-bridge | <2.6.1 |
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CVE-2021-32659 is a vulnerability in Matrix-appservice-bridge, the bridging service for the Matrix communication program's application services.
CVE-2021-32659 affects versions 2.6.0 and earlier of Matrix-appservice-bridge.
CVE-2021-32659 has a severity rating of 4.9 (medium).
To fix CVE-2021-32659, update Matrix-appservice-bridge to version 2.6.1 or later.
You can find more information about CVE-2021-32659 on the official GitHub page of Matrix-appservice-bridge.