CVE-2024-36137 is a vulnerability identified in the Node.js runtime environment, specifically affecting users who utilize the experimental permission model with the --allow-fs-write flag enabled. Node.js introduced this permission model to restrict file system operations; however, it does not enforce permissions on file descriptors. This oversight allows certain file system operations, such as fs.fchown and fs.fchmod, to be executed on file descriptors that are intended to be read-only. Consequently, an attacker or malicious code with limited privileges (requiring low privileges) can change the ownership and permissions of files by exploiting these operations on read-only file descriptors. The vulnerability affects a broad range of Node.js versions, from 4.0 through 22.0, indicating it has been present for multiple major releases. The CVSS v3.0 base score is 3.3, categorized as low severity, reflecting limited impact primarily on integrity without affecting confidentiality or availability. The attack vector is local (AV:L), requiring low privileges (PR:L) but no user interaction (UI:N). There are no known exploits in the wild at the time of publication, and no patches or mitigations have been explicitly linked yet. This vulnerability is significant mainly for environments that actively use the experimental permission model with the --allow-fs-write flag, which is not a default configuration. The core issue lies in the permission model's failure to enforce restrictions on file descriptor operations, allowing unauthorized modification of file ownership and permissions, which could lead to privilege escalation or unauthorized file access modifications within the local system context.

For European organizations, the impact of CVE-2024-36137 is generally limited due to its low severity and the requirement for local access with low privileges. However, organizations that deploy Node.js applications using the experimental permission model and enable the --allow-fs-write flag could face integrity risks where unauthorized users or processes might alter file ownership or permissions. This could lead to unauthorized access or modification of sensitive files, potentially facilitating further privilege escalation or lateral movement within internal networks. Sectors with high reliance on Node.js for backend services, such as financial services, telecommunications, and critical infrastructure providers, might find this vulnerability more relevant if they use experimental features. The vulnerability does not affect confidentiality or availability directly but could undermine system integrity and trustworthiness of file permissions. Given the broad range of affected Node.js versions, legacy systems or development environments that have not updated Node.js might be exposed. Since no known exploits exist in the wild, the immediate risk is low, but the vulnerability could be leveraged in targeted attacks if combined with other local access exploits.

1. Avoid using the experimental permission model with the --allow-fs-write flag in production environments until a patch or official fix is released. 2. If the experimental permission model is required, restrict local user access rigorously to prevent untrusted users from executing code or commands that could exploit this vulnerability. 3. Monitor and audit file ownership and permission changes on critical systems to detect unauthorized modifications promptly. 4. Implement strict access controls and sandboxing for Node.js processes, limiting the ability of processes to perform file system operations beyond their intended scope. 5. Keep Node.js versions updated and watch for official patches addressing this vulnerability; apply them promptly once available. 6. Conduct code reviews and security assessments for applications using the experimental permission model to identify and mitigate potential misuse of file descriptor operations. 7. Employ host-based intrusion detection systems (HIDS) to alert on suspicious file system changes that could indicate exploitation attempts. 8. Educate developers and system administrators about the risks of using experimental features and the importance of adhering to secure configuration practices.