CVE-2022-29166 is a security vulnerability classified under CWE-74, which involves improper neutralization of special elements in output used by a downstream component, leading to injection attacks. The affected software is matrix-appservice-irc, a Node.js-based IRC bridge for the Matrix communication protocol. This bridge enables interoperability between Matrix and IRC networks by relaying messages between the two. The vulnerability arises from the node-irc library used within matrix-appservice-irc, where an attacker can craft malicious messages that, when replied to by a Matrix user in an IRC-bridged room, cause the execution of unintended IRC commands. This occurs because the input is not properly sanitized before being passed downstream to the IRC component, allowing injection of IRC commands. The exploitation requires the victim to reply to a maliciously crafted message, which means user interaction is necessary. The vulnerability affects all versions of matrix-appservice-irc prior to 0.34.0 and has been patched in version 0.33.2 and later. There are no known workarounds other than avoiding replying to messages from untrusted participants in IRC-bridged Matrix rooms. No known exploits have been observed in the wild to date. The attack vector is limited to environments where matrix-appservice-irc is deployed and actively bridging IRC and Matrix communications, which are typically used in organizations or communities relying on both protocols for messaging. The vulnerability impacts the integrity and potentially the availability of IRC communications by allowing injection of arbitrary IRC commands, which could disrupt channels or impersonate users. Confidentiality impact is limited but could arise if injected commands lead to information disclosure on IRC channels.

For European organizations using matrix-appservice-irc to bridge IRC and Matrix communications, this vulnerability poses a risk of command injection on IRC networks via Matrix user interactions. The integrity of IRC channels can be compromised, potentially allowing attackers to manipulate channel states, send unauthorized commands, or impersonate users. This could disrupt communication workflows, damage organizational reputation, and lead to operational downtime. While no direct data exfiltration is indicated, the injection of IRC commands could be leveraged for further attacks or social engineering. Organizations relying on IRC for critical communications, especially in sectors like government, finance, or critical infrastructure, may face increased risk of disruption. The requirement for user interaction (replying to a malicious message) somewhat limits the attack scope but does not eliminate risk, particularly in large or open IRC-bridged Matrix rooms where untrusted participants may be present. The lack of known exploits in the wild suggests limited current threat activity, but the presence of a patch indicates the vulnerability is recognized and should be addressed promptly to prevent future exploitation.

1. Upgrade matrix-appservice-irc to version 0.34.0 or later immediately to apply the official patch that neutralizes the injection vulnerability. 2. Implement strict access controls on IRC-bridged Matrix rooms to limit participation to trusted users only, reducing exposure to malicious actors. 3. Educate users about the risk of replying to messages from untrusted or unknown participants in IRC-bridged rooms, emphasizing cautious interaction. 4. Monitor IRC and Matrix bridge logs for unusual command activity or unexpected message patterns that could indicate attempted exploitation. 5. Where possible, configure the bridge to sanitize or filter user inputs further before passing them to IRC to add an additional layer of defense. 6. Consider segmenting IRC-bridged rooms used for sensitive communications from public or less trusted groups to minimize attack surface. 7. Regularly review and update dependencies, including node-irc, to ensure all components are up to date with security fixes. 8. Establish incident response procedures specific to communication platform compromises to quickly address any detected misuse.