CVE-2025-50681 is a remote denial-of-service vulnerability found in igmpproxy versions before commit 2b30c36. The root cause lies in the recv_igmp() function within src/igmpproxy.c, where insufficient validation of IGMPv3 membership report packets allows an attacker to send malformed multicast traffic containing an invalid group record type. When igmpproxy attempts to log the source address using inet_fmtsrc(), this invalid input causes a NULL pointer dereference, resulting in an application crash. Igmpproxy is widely deployed in embedded networking environments and consumer-grade IoT devices, including home routers and media gateways, which handle multicast traffic for IPTV and streaming services. The vulnerability can be exploited remotely over a local area network without requiring authentication or user interaction, making it accessible to attackers with network access. Although no public exploits have been reported, the flaw poses a significant risk of service disruption, particularly in environments relying heavily on multicast traffic. The lack of a CVSS score necessitates an independent severity assessment, considering the impact on availability and the ease of triggering the crash. This vulnerability could lead to denial of service conditions, interrupting multicast streaming and potentially affecting network stability in consumer and enterprise settings.

For European organizations, this vulnerability poses a risk of denial-of-service attacks that can disrupt multicast-based services such as IPTV and other streaming applications commonly used in corporate and residential networks. Service providers and enterprises relying on igmpproxy-enabled devices may experience network outages or degraded quality of service, impacting business continuity and user experience. In critical infrastructure or media distribution networks, such disruptions could lead to financial losses and reputational damage. The attack requires only local network access, which could be achieved by malicious insiders or compromised devices within the LAN, increasing the threat surface. Additionally, IoT devices with limited security controls may be easier to compromise or misuse as attack vectors. The overall impact includes reduced availability of multicast services and potential cascading effects on dependent applications and services.

Organizations should prioritize updating igmpproxy to the fixed version that includes the commit 2b30c36 or later, which addresses the input validation flaw. Where direct updates to igmpproxy are not feasible, applying vendor-supplied firmware updates for affected routers and media gateways is critical. Network administrators should implement network segmentation and strict access controls to limit exposure of multicast traffic to trusted devices only. Monitoring multicast traffic for anomalous or malformed IGMPv3 packets can help detect exploitation attempts. Employing intrusion detection systems (IDS) with signatures targeting malformed IGMP packets may provide early warning. Additionally, disabling unnecessary multicast services or IGMP proxying on devices where multicast is not required can reduce the attack surface. Regular vulnerability scanning and asset inventory to identify devices running vulnerable igmpproxy versions will aid in targeted remediation efforts.