GHSA-xvqg-mv25-rwvw

### Impact

Attackers can specify a specific string of characters, which would confuse the bridge into combining an attacker-owned channel and an existing channel, allowing them to grant themselves permissions in the channel.

### Patched

The vulnerability has been patched in matrix-appservice-irc 0.35.0.

### Workarounds

Disable dynamic channel joining via `dynamicChannels.enabled` to prevent users from joining new channels, which prevents any new channels being bridged outside of what is already bridged, and what is specified in the config.

### References

- https://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severity

### Credits

Discovered and reported by [Val Lorentz](https://valentin-lorentz.fr/).

### For more information

If you have any questions or comments about this advisory email us at [[email protected]](mailto:[email protected]).