CVE-2021-47564 is a vulnerability identified in the Linux kernel specifically affecting the Marvell Prestera network driver. The issue arises from improper error path handling in the function prestera_bridge_port_join(), which can lead to a double free condition. This double free occurs when the error handling code attempts to free memory or resources that have already been released, causing the Prestera driver to crash. The crash is evidenced by an internal kernel error (Oops) with a specific error code (96000044) and a stack trace pointing to functions within the Prestera driver such as prestera_bridge_destroy and prestera_bridge_port_join. This vulnerability can cause a denial of service (DoS) by crashing the kernel module responsible for managing network bridge ports on devices using the Prestera driver. The Prestera driver is used in network interface cards and switches based on Marvell Prestera silicon, which are common in enterprise and carrier-grade networking equipment running Linux. The vulnerability was fixed by correcting the error path handling to prevent the double free condition. There is no CVSS score assigned yet, and no known exploits in the wild have been reported as of the publication date. The vulnerability affects specific Linux kernel versions identified by commit hashes, indicating it is present in certain kernel builds prior to the fix. This issue is significant because a kernel crash can lead to system instability, loss of network connectivity, and potential disruption of services relying on affected network hardware.

For European organizations, the impact of CVE-2021-47564 can be substantial, particularly for those relying on Linux-based network infrastructure that incorporates Marvell Prestera hardware. A successful exploitation leading to a kernel crash would result in denial of service, disrupting network operations and potentially affecting critical business services, data center connectivity, and cloud infrastructure. This could impact telecommunications providers, internet service providers, data centers, and enterprises with large-scale networking equipment. The loss of network availability can also affect compliance with regulations requiring high availability and data integrity, such as GDPR mandates for data protection and operational continuity. While the vulnerability does not appear to allow privilege escalation or remote code execution, the resulting DoS can be leveraged in targeted attacks to degrade network reliability or as part of a broader attack chain. Given the kernel-level nature of the vulnerability, recovery may require system reboots and patch deployments, which can be operationally disruptive.

To mitigate CVE-2021-47564, European organizations should: 1) Identify if their Linux systems use the Marvell Prestera driver by auditing kernel modules and hardware inventory. 2) Apply the latest Linux kernel updates that include the fix for this vulnerability, ensuring that the patched version replaces affected kernel builds. 3) Where immediate patching is not possible, consider isolating affected systems or limiting network exposure to reduce the risk of triggering the vulnerability. 4) Monitor system logs and kernel messages for signs of crashes or Oops errors related to the Prestera driver to detect potential exploitation attempts. 5) Engage with hardware vendors and network equipment providers to confirm firmware and driver versions and receive guidance on updates. 6) Implement robust network segmentation and redundancy to minimize the impact of potential DoS events on critical services. 7) Incorporate this vulnerability into incident response and vulnerability management workflows to ensure timely detection and remediation.