CVE-2023-52473 is a vulnerability identified in the Linux kernel's thermal management subsystem. Specifically, it involves a NULL pointer dereference occurring in the error handling path of the thermal zone device registration process. The vulnerability arises when the function device_register() within thermal_zone_device_register_with_trips() returns an error. In this scenario, the thermal zone device pointer (tz) is set to NULL but is subsequently dereferenced in a call to kfree(tz->tzp), leading to a NULL pointer dereference and potential kernel crash (denial of service). The root cause is linked to a code change where tz was assigned NULL to avoid a double-free after dropping the reference to the zone device. However, a later commit changed the memory management behavior such that the zone object is no longer freed when the reference is dropped, rendering the NULL assignment redundant and causing the unsafe dereference. This vulnerability can cause system instability or crashes if triggered, impacting the availability of affected Linux systems. It does not appear to allow privilege escalation or code execution directly but can be exploited to cause denial of service. No known exploits are reported in the wild as of the publication date. The issue affects Linux kernel versions identified by the commit hash 3d439b1a2ad36c8b4ea151c8de25309d60d17407, indicating a specific range of kernel versions used in various distributions. The vulnerability was published on February 25, 2024, and is confirmed by the Linux project with no CVSS score assigned yet. The fix involves correcting the error handling logic to avoid dereferencing a NULL pointer, ensuring robust memory management in the thermal subsystem.

For European organizations, the primary impact of CVE-2023-52473 is the potential for denial of service on Linux-based systems that utilize the affected kernel versions. This could disrupt critical infrastructure, enterprise servers, cloud environments, and embedded systems relying on Linux for thermal management. Systems managing thermal zones are common in data centers, industrial control systems, and IoT devices, all of which are prevalent in Europe’s technology landscape. A successful exploitation could lead to unexpected system crashes, causing downtime and operational disruption. While this vulnerability does not directly compromise confidentiality or integrity, the availability impact can be significant, especially for organizations with high uptime requirements such as financial institutions, healthcare providers, and manufacturing plants. Additionally, repeated crashes could complicate incident response and recovery efforts. Since no known exploits are currently reported, the risk of immediate widespread attacks is low; however, the vulnerability’s presence in widely deployed Linux kernels means that European organizations should prioritize patching to prevent future exploitation attempts.

European organizations should implement the following specific mitigation steps: 1) Identify all Linux systems running affected kernel versions by auditing kernel versions across servers, workstations, and embedded devices. 2) Apply the official Linux kernel patches that address CVE-2023-52473 as soon as they become available from trusted sources such as distribution vendors (e.g., Debian, Ubuntu, Red Hat, SUSE). 3) For systems where immediate patching is not feasible, consider temporarily disabling or limiting thermal zone device registration features if possible, or implement kernel-level monitoring to detect abnormal crashes related to thermal subsystem errors. 4) Enhance system monitoring and alerting to detect kernel panics or crashes that could indicate exploitation attempts. 5) Incorporate this vulnerability into vulnerability management and incident response plans to ensure rapid remediation and recovery. 6) Coordinate with hardware and embedded device vendors to verify if their Linux-based products are affected and request firmware or kernel updates. 7) Educate system administrators about the importance of maintaining updated kernels and the risks of unpatched thermal subsystem vulnerabilities.