CVE-2023-52492 is a medium-severity vulnerability in the Linux kernel's DMA engine subsystem. The issue arises from improper handling of a NULL pointer during the unregistration of DMA channels. Specifically, the function __dma_async_device_channel_register() can fail, leading to the freeing and nullification of chan->local. However, the subsequent function __dma_async_device_channel_unregister() unconditionally attempts to unregister channels without checking if chan->local is NULL. This results in a NULL pointer dereference and a kernel crash (kernel panic) as evidenced by the kernel logs showing an inability to handle the NULL pointer dereference at a low virtual address. The root cause is a missing conditional check in the unregistration function to verify chan->local is not NULL before proceeding. The fix involves adding this conditional check to prevent the NULL pointer dereference regardless of the API path taken. This vulnerability is classified under CWE-476 (NULL Pointer Dereference) and affects certain Linux kernel versions identified by specific commit hashes. The CVSS v3.1 score is 4.4, reflecting a medium severity with a local attack vector, low complexity, requiring high privileges, no user interaction, and impacting availability only (causing denial of service via kernel crash). No known exploits are currently reported in the wild. The vulnerability could cause system instability or denial of service on affected Linux systems running vulnerable kernel versions, particularly impacting systems that utilize the DMA engine for asynchronous device channel management.

For European organizations, the primary impact of CVE-2023-52492 is the potential for denial of service (DoS) on Linux-based systems that use the DMA engine subsystem. This could lead to unexpected kernel panics and system reboots, disrupting critical services and operations. Organizations relying on Linux servers, embedded devices, or network infrastructure that utilize DMA channels may experience service outages or degraded performance. While the vulnerability does not allow for privilege escalation or data compromise, the availability impact can be significant in environments requiring high uptime, such as financial institutions, healthcare providers, industrial control systems, and telecommunications. The requirement for high privileges to exploit limits the risk to local users or attackers with administrative access, but insider threats or compromised privileged accounts could trigger the issue. Given the widespread use of Linux in European data centers, cloud environments, and IoT devices, the vulnerability poses a moderate operational risk if unpatched. Additionally, sectors with stringent availability requirements and regulatory compliance (e.g., GDPR mandates on service continuity) may face indirect compliance risks if service disruptions occur.

1. Apply the official Linux kernel patches that address CVE-2023-52492 as soon as they become available from trusted sources or distribution vendors. 2. For organizations using custom or embedded Linux kernels, ensure kernel maintainers backport the fix to all supported versions. 3. Restrict administrative access to systems running vulnerable kernels to minimize the risk of exploitation by unauthorized users. 4. Implement monitoring and alerting for kernel panics or unexpected reboots that could indicate attempts to trigger this vulnerability. 5. Conduct regular audits of privileged user activities to detect potential misuse that could exploit this vulnerability. 6. In environments where patching is delayed, consider isolating vulnerable systems or limiting access to trusted administrators only. 7. Coordinate with hardware and device vendors to confirm DMA engine usage and assess exposure. 8. Incorporate this vulnerability into incident response and risk management plans to ensure rapid remediation and recovery if exploitation occurs.