CVE-2023-32003 in Node.js
Summary
by MITRE • 08/15/2023
`fs.mkdtemp()` and `fs.mkdtempSync()` can be used to bypass the permission model check using a path traversal attack. This flaw arises from a missing check in the fs.mkdtemp() API and the impact is a malicious actor could create an arbitrary directory. This vulnerability affects all users using the experimental permission model in Node.js 20. Please note that at the time this CVE was issued, the permission model is an experimental feature of Node.js.
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Analysis
by VulDB Data Team • 07/03/2025
The vulnerability identified as CVE-2023-32003 represents a critical security flaw in Node.js version 20's experimental permission model, specifically within the filesystem module's temporary directory creation functions. This issue stems from the fs.mkdtemp() and fs.mkdtempSync() APIs which are designed to create temporary directories with secure permissions but fail to properly validate path inputs. The flaw allows malicious actors to exploit path traversal techniques to bypass the intended permission checks and create directories anywhere within the filesystem, effectively undermining the security boundaries established by the experimental permission model.
The technical implementation of this vulnerability occurs at the API level where the fs.mkdtemp() function lacks proper validation of the directory path parameter against the permission model's access controls. When users invoke these functions with carefully crafted path traversal sequences, the underlying implementation fails to sanitize or verify the absolute or relative paths, allowing arbitrary directory creation outside of the designated temporary directories. This behavior directly violates the fundamental security principle that temporary directory operations should be confined to predefined safe locations, as established by the experimental permission model's design. The vulnerability manifests as a path traversal attack vector that exploits the absence of input validation, enabling attackers to escape the intended sandboxed environment.
The operational impact of this vulnerability is significant for Node.js 20 users who have enabled the experimental permission model, as it completely undermines the security guarantees that the feature was designed to provide. An attacker could leverage this flaw to create malicious directories in sensitive locations, potentially leading to privilege escalation, data manipulation, or the creation of persistent backdoors. The vulnerability affects the core functionality of the permission model by allowing unauthorized filesystem modifications that should have been restricted. This creates a scenario where the experimental security feature becomes a liability rather than a protection mechanism, as it enables attackers to bypass the very controls meant to prevent unauthorized access. The impact extends beyond simple directory creation, as it could enable more sophisticated attacks that exploit the compromised permission boundaries.
Mitigation strategies for CVE-2023-32003 focus on both immediate remediation and long-term security architecture improvements. The most effective immediate solution involves disabling the experimental permission model in Node.js 20 until the vulnerability is patched by the Node.js development team, as this feature remains experimental and contains known security flaws. Organizations should also implement additional input validation measures at the application level, ensuring that all paths passed to fs.mkdtemp() functions are properly sanitized and validated against expected safe directories. Security practitioners should monitor the Node.js release notes for patches addressing this vulnerability, as the experimental nature of the permission model means that the issue may be resolved through either a complete implementation fix or by deprecating the affected APIs. The vulnerability aligns with CWE-22 Path Traversal and ATT&CK techniques related to privilege escalation and persistence, making it particularly concerning for environments where Node.js applications handle sensitive data or operate with elevated privileges.