CVE-2021-47524 is a vulnerability identified in the Linux kernel, specifically within the serial subsystem's liteuart driver. The issue pertains to a minor-number leak during probe errors. When the liteuart driver attempts to initialize a device, it allocates a minor number to represent the device instance. However, if an error occurs during the probe process, the allocated minor number is not properly released, leading to a resource leak. This flaw is a memory/resource management bug rather than a direct code execution or privilege escalation vulnerability. While the vulnerability does not directly allow attackers to execute arbitrary code or gain elevated privileges, the leak of minor numbers could potentially lead to resource exhaustion over time, especially on systems that frequently load and unload the liteuart driver or experience repeated probe failures. This could degrade system stability or availability. The vulnerability has been addressed by ensuring that the allocated minor number is released correctly upon probe errors, preventing the leak. There are no known exploits in the wild targeting this vulnerability, and no CVSS score has been assigned yet. The affected versions are identified by specific commit hashes, indicating that this is a relatively recent fix in the Linux kernel source code. The vulnerability is technical and low-level, affecting the kernel's device driver management, which is critical for hardware communication and system stability.

For European organizations, the impact of CVE-2021-47524 is primarily related to system reliability and availability rather than direct compromise of confidentiality or integrity. Organizations running Linux systems with the liteuart driver enabled, especially those using hardware that relies on this driver, could experience resource leaks leading to minor number exhaustion. Over time, this could cause device initialization failures or kernel instability, potentially disrupting services dependent on serial communication. Industrial control systems, embedded devices, or telecommunications infrastructure using Linux with liteuart support might be more susceptible to operational disruptions. However, since exploitation requires repeated probe errors and does not grant direct unauthorized access or privilege escalation, the threat to data confidentiality and integrity is minimal. The absence of known exploits reduces immediate risk, but unpatched systems could face degraded performance or availability issues, which in critical infrastructure or high-availability environments could have operational and financial consequences.

To mitigate this vulnerability, European organizations should: 1) Apply the latest Linux kernel updates that include the patch fixing the minor-number leak in the liteuart driver. 2) Audit systems to identify if the liteuart driver is in use, particularly on devices with serial communication hardware. 3) Monitor system logs for repeated probe errors related to the liteuart driver, which could indicate potential resource leaks or hardware issues. 4) Implement proactive resource monitoring to detect unusual depletion of device minor numbers or related kernel resources. 5) For embedded or industrial systems where kernel updates may be slower, consider isolating affected devices or applying vendor-specific patches. 6) Engage with hardware and Linux distribution vendors to ensure timely updates and support. 7) Incorporate this vulnerability into vulnerability management and patching workflows to ensure it is tracked and remediated promptly.