CVE-2024-31949 is a vulnerability identified in FRRouting (FRR), a widely used open-source routing software suite, up to version 9.1. The issue arises when FRR processes a Multiprotocol Graceful Restart (MP/GR) capability as a dynamic capability in routing protocol messages. Specifically, malformed data in this capability causes a pointer within the code to fail to advance correctly, resulting in an infinite loop during message processing. This infinite loop leads to a denial of service (DoS) condition by consuming excessive CPU resources, potentially causing the routing daemon to become unresponsive or crash. The vulnerability is exploitable remotely without any authentication (AV:N/PR:N), but requires user interaction (UI:R) in the form of receiving crafted routing protocol packets from a peer or attacker. The CVSS v3.1 base score is 6.5, reflecting a medium severity primarily due to the impact on availability without affecting confidentiality or integrity. No patches or exploits are currently publicly available, but the issue is documented and published as of April 2024. FRR is commonly deployed in Internet Service Providers (ISPs), data centers, and enterprise networks to manage routing protocols such as BGP and OSPF, making this vulnerability relevant for network infrastructure stability.

For European organizations, the primary impact of CVE-2024-31949 is the potential for denial of service on critical routing infrastructure. Disruption of FRR routing daemons can lead to network outages, degraded performance, or routing instability, affecting business continuity and service availability. This is particularly critical for ISPs, cloud providers, and large enterprises relying on FRR for dynamic routing. While the vulnerability does not compromise data confidentiality or integrity, the loss of availability can indirectly impact operations and customer trust. Given the reliance on FRR in backbone and edge routing within Europe, successful exploitation could disrupt internet connectivity or internal network communications. The lack of known exploits reduces immediate risk, but the medium severity score and ease of remote exploitation warrant proactive mitigation.

Organizations should monitor FRRouting project communications for official patches addressing CVE-2024-31949 and apply updates promptly once released. In the interim, network administrators can implement ingress filtering to block malformed or unexpected MP/GR capability messages from untrusted peers. Deploying rate limiting on routing protocol traffic can reduce the risk of resource exhaustion. Network segmentation and strict peer authentication can limit exposure to potentially malicious routing updates. Additionally, monitoring FRR daemon health and setting automated restart policies can help recover from potential DoS conditions. Conducting regular security assessments of routing infrastructure and maintaining up-to-date software versions will further reduce risk.