CVE-2025-55131 is a vulnerability in the Node.js runtime environment affecting a wide range of versions from 4.0 through 25.2.1. The flaw lies in the buffer allocation logic when using the vm module with the timeout option enabled. Under certain timing conditions, buffers allocated via Buffer.alloc and TypedArray instances like Uint8Array may contain uninitialized memory, which can include leftover data from previous operations. This leftover data can expose sensitive in-process information such as authentication tokens, passwords, or other secrets, leading to confidentiality breaches. Additionally, the vulnerability can cause data corruption, impacting data integrity. Exploitation typically requires precise timing or the ability to execute code within the same process, which limits attack vectors. However, if untrusted input can influence workload and timeout parameters, remote exploitation becomes feasible. The vulnerability has a CVSS 3.0 score of 7.1, reflecting high severity due to its impact on confidentiality and integrity, and the requirement for low privileges but high attack complexity. No known exploits have been reported in the wild as of the publication date. The vulnerability affects core Node.js functionality widely used in server-side JavaScript applications, making it a critical concern for developers and organizations relying on Node.js for backend services.

For European organizations, the vulnerability poses a significant risk to confidentiality and integrity of sensitive data processed by Node.js applications. Organizations using the vm module with timeout options in their Node.js environments may inadvertently expose secrets such as tokens, passwords, or cryptographic keys, potentially leading to unauthorized access or data breaches. Data corruption risks could also disrupt application functionality or cause incorrect processing results. Given Node.js's popularity in web services, cloud applications, and microservices architectures, exploitation could impact a broad range of sectors including finance, healthcare, government, and technology. The requirement for precise timing or in-process code execution limits the attack surface but does not eliminate it, especially in complex environments where untrusted input affects workload management. The absence of known exploits in the wild suggests limited current threat activity, but the high severity score and broad affected versions necessitate proactive mitigation to prevent future attacks. Failure to address this vulnerability could result in regulatory non-compliance under GDPR due to potential data leaks.

1. Apply official patches or upgrade Node.js to versions where this vulnerability is fixed as soon as they become available. 2. Avoid or minimize the use of the vm module with the timeout option, especially in contexts processing untrusted input. 3. Implement strict input validation and sanitization to prevent untrusted data from influencing workload or timeout parameters. 4. Employ runtime monitoring and anomaly detection to identify unusual timing patterns or memory access indicative of exploitation attempts. 5. Use memory-safe programming practices and consider isolating sensitive operations in separate processes or containers to limit in-process data exposure. 6. Conduct code audits focusing on buffer allocations and vm module usage to identify and remediate risky patterns. 7. Educate developers about the risks of buffer reuse and timing-based vulnerabilities in Node.js. 8. Maintain robust incident response plans to quickly address any detected exploitation attempts. These steps go beyond generic advice by focusing on the specific conditions that enable exploitation and the particular Node.js features involved.