CVE-2021-47443 is a medium-severity vulnerability identified in the Linux kernel's NFC (Near Field Communication) subsystem, specifically within the digital target (digital_tg) implementation. The issue arises in the function digital_tg_listen_mdaa(), where a memory allocation for a parameter structure ('params') occurs. If the subsequent call to digital_send_cmd() fails, the allocated memory for 'params' is not freed, resulting in a memory leak. This flaw is due to improper error handling and resource management in the NFC digital target code path. While the vulnerability does not directly impact confidentiality or integrity, it affects availability by potentially causing resource exhaustion on systems that repeatedly trigger this failure condition. The CVSS 3.1 score is 5.5 (medium), reflecting that the attack vector requires local access (AV:L), low complexity (AC:L), privileges (PR:L), no user interaction (UI:N), and impacts availability (A:H) without affecting confidentiality or integrity. The vulnerability has been fixed by ensuring that the 'params' memory is freed when digital_send_cmd() fails, preventing the leak. No known exploits are reported in the wild as of the publication date (May 22, 2024). The affected versions correspond to specific Linux kernel commits prior to the fix. This vulnerability is relevant to systems using NFC digital target functionality, which may be embedded in devices supporting NFC communications, such as IoT devices, mobile devices running Linux, or specialized industrial equipment.

For European organizations, the impact of CVE-2021-47443 is primarily related to system availability and stability rather than data breach or integrity compromise. Organizations that deploy Linux-based systems with NFC digital target capabilities—such as contactless payment terminals, access control systems, or IoT devices—may experience gradual degradation or denial of service due to memory leaks if the vulnerability is triggered repeatedly. This could disrupt business operations relying on NFC interactions, especially in sectors like retail, transportation, and manufacturing where NFC is commonly used. However, the requirement for local privileges to exploit the vulnerability limits the risk of remote attacks. The absence of known exploits reduces immediate threat levels but does not eliminate the risk of future exploitation. European organizations with stringent uptime and reliability requirements should prioritize patching to avoid potential service interruptions. Additionally, embedded Linux devices with limited memory resources are more susceptible to adverse effects from memory leaks, potentially leading to device crashes or reboots.

To mitigate CVE-2021-47443, European organizations should: 1) Apply the latest Linux kernel updates that include the fix for this vulnerability as soon as possible, ensuring that the patch properly frees allocated memory on failure paths in the NFC digital target code. 2) Audit and monitor systems that utilize NFC digital target functionality for abnormal memory usage patterns or crashes that could indicate exploitation attempts or triggering of the memory leak. 3) Limit local access to systems with NFC capabilities by enforcing strict access controls and user privilege management to reduce the risk of exploitation by unauthorized users. 4) For embedded or IoT devices running Linux with NFC features, coordinate with device vendors to obtain firmware updates incorporating the fix or consider device replacement if updates are unavailable. 5) Implement system resource monitoring and automated alerts to detect early signs of resource exhaustion potentially caused by memory leaks. 6) Conduct regular security assessments and penetration testing focusing on NFC subsystems to identify any residual or related vulnerabilities.