CVE-2021-47023 is a high-severity vulnerability affecting the Linux kernel, specifically within the Marvell Prestera network driver subsystem. The flaw arises during the initialization of network ports where port event handling occurs concurrently. The root cause is a race condition leading to a kernel crash triggered by improper handling of port state transitions. Specifically, the firmware may send an initial port event indicating a 'down' state while the port is still being created, causing the kernel to call cancel_delayed_work() on a work item that may not be valid or properly synchronized. This results in a kernel paging fault and an 'Oops' error, indicative of a kernel panic or crash. The vulnerability is linked to the cancel_delayed_work() function being invoked without verifying the previous port state, which the patch addresses by only canceling port stats work if the port was previously 'up and running.' The crash log shows a memory abort due to invalid page table entries, confirming a use-after-free or null pointer dereference scenario. This vulnerability is categorized under CWE-400 (Uncontrolled Resource Consumption), implying that exploitation could lead to denial of service by crashing the kernel. The CVSS 3.1 score is 8.2 (high), reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and a significant impact on availability, though confidentiality is unaffected and integrity impact is limited. No known exploits are currently reported in the wild, but the vulnerability affects Linux kernel versions containing the Marvell Prestera driver, which is used in network equipment and embedded systems relying on this hardware. The patch involves conditional cancellation of delayed work based on port state, preventing the race condition and subsequent crash.

For European organizations, the primary impact of CVE-2021-47023 is the potential for denial of service (DoS) on Linux systems running the affected kernel with Marvell Prestera network drivers. This could disrupt network connectivity and availability of critical services, especially in environments relying on embedded Linux devices or network infrastructure hardware using this driver. Industries such as telecommunications, cloud service providers, data centers, and enterprises with specialized networking equipment may experience service interruptions. While confidentiality and data integrity are not directly impacted, the availability impact can lead to operational downtime, affecting business continuity and potentially causing financial and reputational damage. Given the kernel-level nature of the crash, recovery may require system reboots or manual intervention, which can be problematic in high-availability or real-time systems. European organizations with deployments of network devices or embedded systems using Marvell Prestera chips should be particularly vigilant. The lack of known exploits reduces immediate risk, but the low complexity and no privilege requirements mean attackers could potentially develop exploits, increasing future risk.

1. Apply the official Linux kernel patch that addresses this vulnerability as soon as it becomes available for your distribution or kernel version. Monitor vendor advisories for updated kernel packages. 2. Identify and inventory all systems using the Marvell Prestera network driver, including embedded devices and network appliances, to prioritize patching efforts. 3. For devices where patching the kernel is not immediately feasible, consider network segmentation and access controls to limit exposure to untrusted networks, reducing the risk of remote exploitation. 4. Implement monitoring and alerting for kernel crashes and unusual network port events to detect potential exploitation attempts early. 5. Engage with hardware and device vendors to confirm if their products are affected and request firmware or driver updates if applicable. 6. In environments with strict uptime requirements, plan for maintenance windows to apply patches and reboot affected systems safely. 7. Maintain up-to-date backups and recovery procedures to minimize downtime impact in case of crashes triggered by exploitation attempts.