CVE-2024-56643 is a vulnerability identified in the Linux kernel's implementation of the Datagram Congestion Control Protocol (DCCP). Specifically, the flaw is a memory leak occurring in the function dccp_feat_change_recv when handling certain feature negotiation scenarios. The issue arises when dccp_feat_push_confirm() fails after a new value for the SP (Service Profile) feature has been accepted but before reconciliation occurs (i.e., when the 'entry == NULL' branch is taken). In this failure case, memory allocated by dccp_feat_clone_sp_val() for the new SP feature value is not freed, resulting in a memory leak. This leak was detected through kernel memory leak detection tools such as kmemleak, with a detailed stack trace showing the allocation and failure path. The root cause is that the allocated memory is not cleaned up upon failure of the confirmation function, leading to unreferenced objects accumulating in kernel memory. The vulnerability is classified under CWE-401 (Improper Release of Memory Before Removing Last Reference) and has been fixed by ensuring proper cleanup of allocated memory in the failure path, returning an error reset code to prevent further processing. The vulnerability affects specific Linux kernel versions identified by commit hashes, and no known exploits are reported in the wild. The CVSS v3.1 base score is 3.3, indicating a low severity, with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L, meaning it requires local access with low privileges and no user interaction, and impacts availability only (memory leak).

For European organizations, the impact of CVE-2024-56643 is generally low but should not be dismissed. The vulnerability causes a memory leak in the Linux kernel's DCCP implementation, which could lead to gradual resource exhaustion on affected systems if exploited repeatedly or over time. This could degrade system performance or cause denial of service conditions on servers or network devices relying on DCCP. However, since DCCP is not widely used compared to TCP or UDP, the attack surface is limited. The requirement for local access and low privileges reduces the risk of remote exploitation. Nonetheless, organizations running Linux systems with DCCP enabled, especially in network infrastructure or specialized applications using DCCP, could experience stability issues or service interruptions if the vulnerability is triggered. This could affect availability of critical services, particularly in telecom, real-time media streaming, or other sectors using DCCP. Given the low CVSS score and absence of known exploits, the immediate risk is low, but the vulnerability could be leveraged as part of a larger attack chain or in insider threat scenarios.

To mitigate CVE-2024-56643, European organizations should: 1) Apply the latest Linux kernel patches that address this memory leak as soon as they become available from their distribution vendors or upstream Linux kernel releases. 2) Audit and monitor systems that use DCCP, especially network-facing servers or specialized applications, to detect abnormal memory usage or leaks. 3) Disable DCCP protocol support if it is not required for operational purposes, reducing the attack surface. This can be done by blacklisting the dccp kernel module or disabling it via kernel configuration. 4) Implement strict access controls to limit local user privileges and prevent untrusted users from triggering the vulnerability. 5) Employ kernel memory leak detection tools like kmemleak in testing environments to proactively identify similar issues. 6) Maintain robust system monitoring and alerting to detect early signs of resource exhaustion or denial of service conditions potentially related to this vulnerability. These steps go beyond generic advice by focusing on protocol usage assessment, kernel module management, and proactive detection.