CVE-2023-23918 in Node.js
Summary
by MITRE • 02/23/2023
A privilege escalation vulnerability exists in Node.js <19.6.1, <18.14.1, <16.19.1 and <14.21.3 that made it possible to bypass the experimental Permissions (https://nodejs.org/api/permissions.html) feature in Node.js and access non authorized modules by using process.mainModule.require(). This only affects users who had enabled the experimental permissions option with --experimental-policy.
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Analysis
by VulDB Data Team • 12/03/2025
The vulnerability identified as CVE-2023-23918 represents a critical privilege escalation flaw within Node.js runtime environments that specifically targets the experimental permissions system introduced to enhance security controls. This weakness exists across multiple Node.js version lines including versions prior to 19.6.1, 18.14.1, 16.19.1, and 14.21.3, creating a widespread impact across the Node.js ecosystem. The vulnerability exploits a fundamental design flaw in how Node.js handles module loading when the experimental permissions feature is enabled through the --experimental-policy flag, undermining the security model that was intended to restrict access to unauthorized modules and system resources.
The technical exploitation of this vulnerability relies on the ability of malicious actors to bypass the intended restrictions by leveraging the process.mainModule.require() method, which provides direct access to the module loading system bypassing the permission checks that should normally be enforced. This mechanism allows attackers to load modules that would otherwise be restricted or denied access to by the experimental permissions system, effectively neutralizing the security controls that were put in place to prevent unauthorized module access. The vulnerability operates at the core of Node.js's module resolution and loading architecture, specifically targeting the gap between the permission enforcement layer and the actual module loading mechanisms that can be accessed through alternative pathways.
When exploited, this vulnerability can lead to significant operational impacts including unauthorized access to sensitive system resources, potential data breaches, and the ability to execute arbitrary code within the Node.js environment. The attack vector is particularly concerning because it only requires the experimental permissions feature to be enabled, which many developers might enable for security reasons, creating a false sense of security while simultaneously exposing the system to more sophisticated attacks. The privilege escalation occurs at runtime when the Node.js process is executing with elevated privileges, potentially allowing attackers to access system files, network resources, and other modules that should be restricted based on the policy configuration.
The mitigation strategy for this vulnerability requires immediate patching of affected Node.js versions to the latest stable releases that contain the fix for the permission bypass mechanism. System administrators and developers should also review their existing experimental policy configurations to ensure that they are not inadvertently exposing systems to this vulnerability. The fix implemented in the patched versions addresses the core issue by properly enforcing permission checks even when alternative module loading pathways such as process.mainModule.require() are utilized. Organizations should also consider implementing additional monitoring and logging mechanisms to detect unauthorized module access attempts, as this vulnerability represents a sophisticated bypass technique that may not be immediately apparent through standard security controls.
This vulnerability aligns with CWE-284 which addresses improper access control mechanisms and can be mapped to ATT&CK technique T1068 which covers "Exploitation for Privilege Escalation" in cybersecurity frameworks. The attack pattern demonstrates how experimental security features, while well-intentioned, can introduce new attack surfaces when not properly implemented or tested against edge cases. The vulnerability specifically targets the Node.js permissions model, which is designed to prevent unauthorized access to system resources through policy-based access control, making it a significant concern for organizations that rely on Node.js applications for critical business operations. The remediation process should include comprehensive testing of all experimental policy configurations to ensure that the patched versions properly enforce access controls without introducing new security gaps or performance regressions.