matrix-appservice-irc vulnerable to IRC mode parameter confusion
ImpactIRC allows you to specify multiple modes in a single mode command. Due to a bug in the underlying matrix-org/node-irc library, affected versions of matrix-appservice-irc perform parsing of such modes incorrectly, potentially resulting in the wrong user being given permissions.Mode commands can only be executed by privileged users, so this can only be abused if an operator is tricked into running the command on behalf of an attacker.PatchesThe vulnerability has been patched in matrix-appservice-irc 0.35.0.WorkaroundsRefrain from entering mode commands suggested by untrusted users. Avoid using multiple modes in a single command.Referenceshttps://matrix.org/blog/2022/09/13/security-release-of-matrix-appservice-irc-0-35-0-high-severityCreditsDiscovered and reported by [Val Lorentz](https://valentin-lorentz.fr/).For more informationIf you have any questions or comments about this advisory email us at [security@matrix.org](mailto:security@matrix.org).