CVE-2024-57791 is a vulnerability identified in the Linux kernel's handling of the SMC (Shared Memory Communications) protocol, specifically within the net/smc subsystem responsible for managing communication over SMC connections. The vulnerability arises from improper validation of the length field in the smc_clc_msg_hdr structure, which indicates the expected length of a message received from the network. Since this length value is sourced from potentially untrusted network input, it should not be fully trusted. However, prior to the patch, if the length value exceeded the buffer length (buflen) in the function smc_clc_wait_msg, the kernel could enter a deadloop while attempting to drain the remaining data exceeding the buffer size. This deadloop could cause the system to hang or become unresponsive, impacting availability. The patch addresses this issue by adding a check on the return value of sock_recvmsg during the draining process, preventing the deadloop condition by properly handling cases where the received data length is inconsistent or excessive. This vulnerability is relevant to Linux kernel versions identified by the commit hash fb4f79264c0fc6fd5a68ffe3e31bfff97311e1f1 and affects systems using the SMC protocol for network communication. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet.

For European organizations, this vulnerability primarily threatens system availability. Systems running affected Linux kernel versions that utilize the SMC protocol could experience denial-of-service conditions if an attacker sends specially crafted network messages with manipulated length fields. This could lead to kernel deadloops, causing affected servers or network devices to hang or become unresponsive. Given that Linux is widely deployed across European enterprises, cloud providers, and critical infrastructure, the impact could be significant, especially in environments relying on SMC for high-performance or specialized network communication. While confidentiality and integrity impacts are not indicated, availability degradation can disrupt business operations, service delivery, and critical communications. Organizations in sectors such as telecommunications, finance, and government that rely on Linux-based infrastructure may face operational risks if this vulnerability is exploited.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2024-57791. Since the vulnerability involves the net/smc subsystem, organizations should audit their use of the SMC protocol and assess whether it is enabled or required in their environments. If SMC is not in use, disabling the net/smc module can reduce exposure. Network-level controls such as filtering or rate limiting traffic that could exploit this vulnerability may also help reduce risk. Monitoring kernel logs for unusual behavior related to SMC message handling can provide early detection of exploitation attempts. Additionally, organizations should implement robust network segmentation to limit exposure of vulnerable systems to untrusted networks. Given the absence of known exploits, proactive patch management and vulnerability scanning focused on kernel versions are critical to prevent potential exploitation.