CVE-2024-35947 addresses a vulnerability in the Linux kernel specifically related to the dynamic debugging (dyndbg) subsystem's control parser. The issue stems from an old BUG_ON macro that has been present since 2009. BUG_ON is a kernel debugging macro that triggers a kernel panic if a certain condition is met, effectively halting the system. In this case, the BUG_ON was considered "unreachable" by the developers, but it was not formally verified or removed until now. The fix replaces this BUG_ON with a safer error handling approach: it logs an error message (pr_err) and returns an error code (-EINVAL), preventing a kernel panic. This change improves the robustness of the kernel by avoiding unexpected crashes triggered by this condition in the dyndbg control parser. The vulnerability has a CVSS 3.1 base score of 5.5 (medium severity), with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), no impact on confidentiality or integrity (C:N/I:N), but high impact on availability (A:H). This means an attacker with local privileges could cause a denial of service (kernel panic) without needing user interaction. The affected versions are identified by a specific commit hash repeated multiple times, indicating the vulnerability is tied to a particular code state in the Linux kernel source. There are no known exploits in the wild at the time of publication, and no patch links were provided in the data, but the fix is integrated into the kernel source. Overall, this vulnerability is a local denial-of-service risk due to a kernel panic triggered by a control parser bug in the dynamic debugging feature of the Linux kernel.

For European organizations, this vulnerability primarily poses a risk of local denial of service on Linux systems running affected kernel versions. Since Linux is widely used in servers, cloud infrastructure, embedded devices, and workstations across Europe, the potential for service disruption exists if an attacker gains local access. The impact is limited to availability, with no direct confidentiality or integrity compromise. However, denial of service in critical infrastructure, financial services, telecommunications, or government systems could lead to operational disruptions, financial losses, or reputational damage. The requirement for local privileges reduces the attack surface, but insider threats or attackers who have already compromised user accounts could exploit this to escalate disruption. Systems using dynamic debugging extensively for troubleshooting or monitoring might be more exposed. Given the medium severity and lack of known exploits, the immediate risk is moderate, but organizations should prioritize patching to prevent potential denial-of-service attacks that could affect service continuity.

1. Apply the latest Linux kernel updates that include the fix for CVE-2024-35947 as soon as they become available from trusted Linux distribution vendors or kernel maintainers. 2. Restrict local access to Linux systems by enforcing strict access controls, limiting user privileges, and monitoring for suspicious local activity to reduce the risk of exploitation. 3. Disable dynamic debugging (dyndbg) if it is not required in production environments to minimize the attack surface related to this subsystem. 4. Implement robust logging and alerting to detect abnormal kernel errors or crashes that could indicate attempts to trigger this vulnerability. 5. Conduct regular kernel version audits and vulnerability assessments to ensure all systems are running patched and supported kernel versions. 6. For critical systems, consider deploying kernel live patching solutions that allow applying security fixes without rebooting, minimizing downtime. 7. Educate system administrators about the risks of local privilege escalation and denial-of-service vulnerabilities to improve operational security practices.