CVE-2024-56591 is a recently published vulnerability affecting the Linux kernel's Bluetooth subsystem, specifically within the hci_conn component responsible for managing Bluetooth connections. The vulnerability arises from improper handling of delayed work synchronization when freeing objects associated with ongoing Bluetooth connection tasks. The original implementation used cancel_delayed_work_sync to cancel ongoing delayed work; however, this function only cancels the current work but does not prevent new work submissions. This can lead to a use-after-free condition where the object holding the delayed work is freed while new work is still being submitted, potentially causing memory corruption or kernel crashes. The fix replaces cancel_delayed_work_sync with disable_delayed_work_sync, which not only cancels ongoing work but also disables the submission of new delayed work, ensuring safe object deallocation. Although no known exploits are currently reported in the wild, this vulnerability could be leveraged by an attacker with local access to cause denial of service or potentially escalate privileges by exploiting kernel memory corruption. The vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, indicating it is present in recent kernel releases prior to the patch. No CVSS score has been assigned yet, and no detailed CWE classification is provided. The vulnerability is technical and low-level, requiring knowledge of kernel internals and Bluetooth stack operations to exploit.

For European organizations, the impact of CVE-2024-56591 could be significant, especially for those relying heavily on Linux-based systems with Bluetooth capabilities. This includes enterprises using Linux servers, embedded devices, IoT infrastructure, and workstations where Bluetooth connectivity is enabled. The vulnerability could allow attackers with local access to cause system instability or crashes, leading to denial of service conditions. In critical environments such as healthcare, manufacturing, or transportation where Linux devices are used for operational technology, such disruptions could have safety and operational repercussions. Additionally, if exploited for privilege escalation, attackers could gain unauthorized control over affected systems, potentially leading to data breaches or lateral movement within networks. Given the widespread use of Linux in European public sector, research institutions, and telecommunications, the vulnerability poses a risk to confidentiality, integrity, and availability of systems. However, exploitation requires local access and some technical sophistication, limiting the threat to targeted attacks rather than broad remote exploitation.

European organizations should prioritize patching Linux kernel versions to incorporate the fix that replaces cancel_delayed_work_sync with disable_delayed_work_sync in the Bluetooth hci_conn component. System administrators should: 1) Identify all Linux systems with Bluetooth enabled and verify kernel versions against the patched commit. 2) Apply kernel updates from trusted Linux distributions promptly to ensure the vulnerability is remediated. 3) Disable Bluetooth functionality on servers and critical infrastructure where it is not required to reduce the attack surface. 4) Implement strict local access controls and monitoring to detect unauthorized attempts to interact with Bluetooth subsystems. 5) Employ kernel hardening techniques such as SELinux or AppArmor profiles to limit the impact of potential kernel exploits. 6) Conduct regular vulnerability scans and penetration tests focusing on kernel and Bluetooth stack security. 7) Educate system users and administrators about the risks of local exploitation and the importance of applying security updates. These steps go beyond generic advice by focusing on Bluetooth-specific controls and kernel patch management tailored to this vulnerability.