CVE-2024-35965 is a vulnerability identified in the Linux kernel's Bluetooth L2CAP (Logical Link Control and Adaptation Protocol) implementation. The issue arises from improper validation of user input passed to the setsockopt system call, which is used to set options on sockets. Specifically, the kernel failed to verify the length of the user-supplied data before copying it, leading to a potential buffer overflow or memory corruption scenario. This vulnerability could allow a local or possibly remote attacker to craft malicious Bluetooth packets or socket options that exploit this flaw to execute arbitrary code, escalate privileges, or cause denial of service by crashing the kernel. The vulnerability affects multiple versions of the Linux kernel, as indicated by the repeated commit hashes, and was publicly disclosed on May 20, 2024. Although no known exploits are currently reported in the wild, the nature of the vulnerability—improper input validation in a widely used kernel subsystem—makes it a significant security concern. The lack of a CVSS score suggests that the severity has not yet been formally assessed, but the technical details imply a potentially high impact if exploited. The fix involves adding proper length checks before copying user input data, mitigating the risk of buffer overflows and related attacks.

For European organizations, this vulnerability poses a considerable risk, especially those relying heavily on Linux-based systems with Bluetooth capabilities. Industries such as manufacturing, healthcare, telecommunications, and critical infrastructure often use Linux servers, embedded devices, and IoT systems that may utilize Bluetooth connectivity. Exploitation could lead to unauthorized system access, data breaches, or service disruptions. Given the kernel-level nature of the flaw, successful exploitation could compromise system integrity and availability, potentially affecting operational technology and sensitive data. Additionally, organizations with remote or mobile workforces using Bluetooth peripherals could be exposed to targeted attacks. The absence of known exploits currently reduces immediate risk but does not eliminate the threat, as attackers may develop exploits following public disclosure. The vulnerability's impact is amplified in environments where patching is delayed or where Bluetooth is enabled by default without strict access controls.

European organizations should prioritize applying the official Linux kernel patches that address this vulnerability as soon as they become available. Until patches are deployed, organizations should consider disabling Bluetooth functionality on critical systems where it is not essential, to reduce the attack surface. Network segmentation and strict access controls should be enforced to limit exposure of vulnerable systems. Monitoring for unusual Bluetooth activity and kernel crashes can help detect attempted exploitation. Additionally, organizations should review and harden Bluetooth security policies, including device pairing and authentication mechanisms. For embedded and IoT devices running vulnerable Linux kernels, vendors should be contacted for firmware updates or mitigations. Security teams should also update intrusion detection and prevention systems with signatures targeting potential exploitation attempts related to L2CAP setsockopt misuse. Finally, maintaining an up-to-date asset inventory to identify all Linux systems with Bluetooth enabled is critical for effective remediation.