CVE-2024-26741 is a vulnerability identified in the Linux kernel's handling of socket connections, specifically within the DCCP/TCP networking stack. The issue arises during the allocation and management of ephemeral ports for unbound sockets when the kernel attempts to add a socket to the established hash table (ehash). Normally, when connect() is called on an unbound socket, the kernel searches for an available ephemeral port and checks if the corresponding hash bucket is reusable. If reusable, the socket is added to the ehash, and the socket's inet_num is set. However, if the subsequent allocation of a secondary hash bucket (bhash2) fails, the kernel must revert the changes made by check_established() to avoid leaving an unconnected socket occupying an ehash entry illegally. The vulnerability occurs because this rollback is not properly handled in rare cases where allocation fails, potentially leaving stale or invalid socket entries in the ehash. This can lead to inconsistent socket state and kernel warnings, as observed in syzkaller fuzzing logs, which reported WARN_ON triggers in inet_csk_destroy_sock(). Although exploitation in the wild is not known and the failure condition is rare, the flaw could cause resource leaks or denial of service by corrupting kernel socket state. The vulnerability was discovered through fuzz testing and fault injection, highlighting a corner case in socket lifecycle management under memory pressure or allocation failure scenarios. The patch involves ensuring proper cleanup and rollback of socket hash entries when allocation fails during connect() processing for unbound sockets.

For European organizations, the impact of CVE-2024-26741 primarily revolves around potential denial of service (DoS) conditions on Linux-based systems, which are widely deployed in enterprise servers, cloud infrastructure, and network appliances. A successful exploitation could cause kernel warnings, resource leaks, or socket state corruption, potentially leading to service disruptions or degraded network functionality. This is particularly critical for organizations relying on high-availability Linux servers for web hosting, telecommunications, or critical infrastructure services. Although no known exploits exist currently, the vulnerability could be leveraged in targeted attacks to destabilize network services or cause kernel crashes under specific conditions, especially in environments with high socket connection churn or constrained memory. European entities operating large-scale Linux deployments, including cloud providers, financial institutions, and government agencies, may face increased risk if attackers develop exploits that trigger this rare allocation failure path. The vulnerability does not appear to allow privilege escalation or remote code execution directly but can be a vector for denial of service or disruption of network communications.

To mitigate CVE-2024-26741, European organizations should: 1) Apply the latest Linux kernel patches that address this vulnerability as soon as they become available, ensuring that all affected systems are updated promptly. 2) Monitor kernel logs for warnings related to inet_csk_destroy_sock() or unusual socket state errors that may indicate attempts to trigger this flaw. 3) Implement resource monitoring and limits to prevent memory pressure scenarios that could increase the likelihood of allocation failures during socket operations. 4) Harden network-facing services by limiting unnecessary socket creation and connection attempts, reducing the attack surface. 5) Employ kernel hardening and security modules that can detect or prevent abnormal socket lifecycle behavior. 6) For critical infrastructure, consider deploying kernel live patching solutions to minimize downtime while applying fixes. 7) Conduct regular fuzz testing and security audits on network stack components to proactively identify similar edge-case vulnerabilities. These steps go beyond generic advice by focusing on proactive detection, resource management, and rapid patch deployment tailored to this specific kernel socket management flaw.