CVE-2023-50784 is a buffer overflow vulnerability identified in the websockets implementation of UnrealIRCd versions 6.1.0 through 6.1.3. UnrealIRCd is an open-source Internet Relay Chat (IRC) server widely used for real-time chat services. The vulnerability arises when an attacker sends an oversized packet to a websocket port if it is open and enabled on the server. This causes a buffer overflow condition, which can crash the IRC server, resulting in a denial of service. On some uncommon or older platforms, the overflow may be exploitable for remote code execution, allowing an attacker to execute arbitrary code with the privileges of the IRC server process. The vulnerability does not require authentication or user interaction, making it remotely exploitable by any attacker who can reach the websocket port. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The vulnerability was published on December 16, 2023, and affects UnrealIRCd versions prior to 6.1.4, which includes the fix. The lack of patch links in the provided data suggests users should consult official UnrealIRCd sources for updates. The vulnerability primarily threatens availability by crashing the server but could also impact confidentiality and integrity on certain legacy platforms if remote code execution is achieved.

For European organizations, the primary impact is denial of service due to server crashes, which can disrupt real-time communication services dependent on UnrealIRCd. This can affect internal communications, customer support channels, and any services relying on IRC infrastructure. On uncommon or older platforms still in use within some organizations, the risk escalates to remote code execution, potentially allowing attackers to gain control over the server, leading to data breaches or further network compromise. The lack of authentication requirement and ease of exploitation increase the threat level. Organizations with exposed websocket ports are particularly vulnerable. Disruptions could affect sectors relying on IRC for coordination, including tech companies, educational institutions, and community networks. The impact on confidentiality and integrity is limited to specific legacy environments but should not be ignored. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits over time.

European organizations should immediately verify if UnrealIRCd versions 6.1.0 through 6.1.3 are in use, especially with websockets enabled. They should upgrade to version 6.1.4 or later, which contains the fix for this vulnerability. If upgrading is not immediately possible, organizations should disable the websocket feature or block access to the websocket port at network perimeter firewalls to prevent exploitation. Network monitoring should be enhanced to detect oversized websocket packets or unusual traffic patterns targeting IRC servers. Implementing strict ingress filtering and limiting exposure of IRC servers to trusted networks can reduce risk. Regularly auditing and updating IRC server software and dependencies is critical. Organizations should also review legacy systems and platforms still in use to assess their susceptibility to remote code execution. Incident response plans should be updated to address potential IRC server compromises. Finally, organizations should stay informed through official UnrealIRCd advisories and security communities for any emerging exploit reports or patches.