CVE-2021-47442 is a vulnerability identified in the Linux kernel's NFC (Near Field Communication) digital subsystem. The issue arises in the function digital_in_send_sdd_req(), where a socket buffer ('skb') is allocated but not properly freed if the subsequent call to digital_in_send_cmd() fails. This improper handling leads to a memory leak, as the allocated memory is not released under failure conditions. The vulnerability is rooted in resource management within the NFC digital driver code, specifically in error handling paths. While the flaw does not directly enable code execution or privilege escalation, persistent memory leaks can degrade system performance and stability over time, potentially leading to denial-of-service (DoS) conditions if exploited at scale or in critical environments. The vulnerability affects multiple Linux kernel versions identified by specific commit hashes, and a fix has been implemented by ensuring that the allocated 'skb' is freed when digital_in_send_cmd() returns a failure. There are no known exploits in the wild targeting this vulnerability, and no CVSS score has been assigned yet. The issue is primarily a reliability and resource management concern within the kernel's NFC stack.

For European organizations, the impact of CVE-2021-47442 is primarily related to system stability and availability rather than direct compromise of confidentiality or integrity. Organizations that rely on Linux-based systems with NFC capabilities—such as those using NFC for access control, contactless payments, or secure communications—may experience gradual degradation of system performance or unexpected crashes if the memory leak accumulates over time. This could disrupt business operations, especially in sectors like finance, transportation, and public services where NFC is commonly deployed. Although exploitation requires triggering the failure condition in digital_in_send_cmd(), which may not be trivial, targeted attacks or faulty NFC interactions could exacerbate the issue. The absence of known exploits reduces immediate risk, but unpatched systems remain vulnerable to potential future exploitation or inadvertent DoS scenarios. Overall, the threat is moderate but warrants timely patching to maintain system reliability and operational continuity.

To mitigate this vulnerability, European organizations should prioritize updating their Linux kernel to the latest patched versions that include the fix for CVE-2021-47442. Specifically, system administrators should: 1) Identify all Linux systems utilizing NFC functionality, particularly those running kernel versions corresponding to the affected commit hashes. 2) Apply vendor-provided kernel updates or patches that address the memory leak in digital_in_send_sdd_req(). 3) If immediate patching is not feasible, consider disabling NFC functionality temporarily on critical systems to prevent triggering the vulnerable code path. 4) Implement monitoring for unusual memory usage patterns or kernel logs that may indicate memory leaks or NFC subsystem errors. 5) Engage with Linux distribution security advisories and maintain an active patch management process to quickly respond to kernel vulnerabilities. These steps go beyond generic advice by focusing on NFC subsystem usage and kernel patch application, which are critical for addressing this specific flaw.