CVE-2020-8252 is a classic buffer overflow vulnerability (CWE-120) found in the Node.js runtime environment, specifically in the implementation of the realpath function within the libuv library versions prior to 10.22.1, 12.18.4, and 14.9.0. Libuv is a multi-platform support library with a focus on asynchronous I/O, and it is a core dependency of Node.js. The vulnerability arises because the realpath implementation incorrectly calculates the buffer size needed to store the resolved absolute path. If the resolved path exceeds 256 bytes, the buffer allocated is insufficient, leading to a buffer overflow condition. This overflow can corrupt adjacent memory, potentially allowing an attacker to execute arbitrary code, cause a denial of service (application crash), or manipulate program control flow. The affected Node.js versions span from 4.0 through 14.0, covering a wide range of legacy and actively used releases. Notably, there are no known exploits in the wild reported for this vulnerability, and no official CVSS score has been assigned. However, the nature of buffer overflow vulnerabilities, especially in a widely used runtime like Node.js, makes this a significant security concern. Exploitation would typically require the attacker to influence the input to the realpath function such that it resolves to a path longer than 256 bytes, which may require some level of access or user interaction depending on the application context. Since Node.js is commonly used in server-side applications, this vulnerability could be leveraged remotely if the vulnerable function is exposed to user inputs or network requests. The absence of patch links in the provided data suggests that users should upgrade to the fixed versions (libuv 10.22.1, 12.18.4, or 14.9.0 and above) to mitigate this issue.

For European organizations, the impact of CVE-2020-8252 can be substantial, especially for those relying heavily on Node.js for backend services, web applications, or microservices architectures. Successful exploitation could lead to arbitrary code execution, allowing attackers to gain unauthorized access, escalate privileges, or disrupt services. This could compromise the confidentiality, integrity, and availability of critical business data and services. Given the widespread adoption of Node.js in sectors such as finance, healthcare, telecommunications, and government services across Europe, the vulnerability poses a risk of service outages, data breaches, and potential regulatory non-compliance under GDPR if personal data is exposed. Additionally, the buffer overflow could be used as a stepping stone for lateral movement within networks, increasing the overall attack surface. While no known exploits are reported, the ease of exploitation depends on the application's exposure and input sanitization. Organizations using older Node.js versions or custom applications that invoke realpath with user-controllable inputs are at higher risk. The vulnerability's presence in multiple major Node.js versions means that many legacy systems remain vulnerable if not updated, increasing the potential attack surface across European enterprises.

1. Immediate upgrade of Node.js to versions that include patched libuv releases: 10.22.1, 12.18.4, 14.9.0, or later. This is the most effective mitigation. 2. Audit and review all application code and dependencies that invoke realpath or similar path resolution functions to ensure inputs are validated and sanitized, preventing attacker-controlled long paths. 3. Implement strict input validation and length checks on file path inputs to prevent excessively long paths that could trigger the overflow. 4. Employ runtime protections such as Address Space Layout Randomization (ASLR), Data Execution Prevention (DEP), and stack canaries to reduce the impact of potential buffer overflow exploitation. 5. Monitor application logs and network traffic for unusual behavior or crashes that could indicate attempted exploitation. 6. For organizations unable to immediately upgrade, consider isolating vulnerable Node.js services behind firewalls or API gateways to limit exposure. 7. Incorporate static and dynamic code analysis tools in the development lifecycle to detect unsafe buffer handling patterns. 8. Engage in regular vulnerability scanning and penetration testing focused on Node.js applications to identify and remediate similar issues proactively.