CVE-2021-47057 is a medium-severity vulnerability identified in the Linux kernel, specifically within the crypto subsystem module sun8i-ss. The issue arises from a memory leak caused when the dma_iv (Direct Memory Access Initialization Vector) mapping operation fails. In this failure scenario, the kernel code does not properly free the allocated memory for the object 'd', leading to a resource leak. This vulnerability is categorized under CWE-770 (Allocation of Resources Without Limits or Throttling), indicating improper resource management. The root cause is a missing error handling path that should release the allocated memory before returning an error status. The fix involves adding a new error return label to ensure that the object 'd' is freed appropriately on failure of dma_iv mapping. The vulnerability does not impact confidentiality or integrity but affects availability due to resource exhaustion risks. The CVSS v3.1 base score is 5.5 (medium), with vector AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H, meaning the attack requires local access with low complexity, privileges, and no user interaction, and it impacts availability only. There are no known exploits in the wild, and no public patches linked yet, but the issue has been acknowledged and fixed in the Linux kernel source. The affected versions correspond to specific Linux kernel commits identified by their hashes. This vulnerability is relevant to systems running the affected Linux kernel versions with the sun8i-ss crypto module enabled, which is commonly found in certain ARM-based SoCs used in embedded devices and some IoT hardware.

For European organizations, the primary impact of CVE-2021-47057 lies in potential denial-of-service conditions caused by memory leaks in affected Linux systems. Organizations relying on embedded Linux devices or ARM-based hardware using the sun8i-ss crypto module could experience degraded system performance or crashes due to resource exhaustion. This could disrupt critical infrastructure, industrial control systems, or IoT deployments prevalent in sectors such as manufacturing, energy, and telecommunications. While the vulnerability does not allow data leakage or unauthorized code execution, the availability impact could lead to operational downtime, impacting business continuity and service reliability. European enterprises with large-scale deployments of embedded Linux devices, especially in environments where physical or remote local access is possible, should be vigilant. The requirement for local privileges limits remote exploitation, but insider threats or compromised local accounts could trigger the vulnerability. Given the growing adoption of Linux-based embedded systems in Europe, the risk is non-negligible for organizations with such infrastructure.

To mitigate CVE-2021-47057, European organizations should: 1) Identify and inventory all Linux systems running kernel versions affected by this vulnerability, focusing on devices using the sun8i-ss crypto module, particularly ARM-based embedded devices. 2) Apply the official Linux kernel patches that address this memory leak as soon as they become available from trusted sources or Linux distributions. 3) For devices where kernel upgrades are not immediately feasible, implement monitoring for unusual memory consumption or resource exhaustion symptoms related to the crypto subsystem. 4) Restrict local access to trusted administrators and enforce least privilege principles to reduce the risk of exploitation by local attackers. 5) Employ host-based intrusion detection systems (HIDS) to detect anomalous behavior that could indicate attempts to trigger the vulnerability. 6) Engage with device vendors to ensure firmware updates include the fix, especially for embedded or IoT devices that may not receive regular kernel updates. 7) Incorporate this vulnerability into vulnerability management and patching workflows to ensure timely remediation and verification.