CVE-2026-58043 in Node.js
Summary
by MITRE • 07/30/2026
A flaw in Node.js Permission Model enforcement can over-grant filesystem access across radix-tree prefix boundaries.
Under `--permission`, an attacker who is granted access to one path can abuse boundary handling to read from or write to paths outside the intended filesystem allowlist.
This vulnerability affects Node.js **main**, **22.x**, **24.x**, and **26.x**.
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Analysis
by VulDB Data Team • 07/30/2026
The vulnerability in Node.js permission model represents a critical security flaw that undermines the fundamental principle of least privilege enforcement within the runtime environment. This issue specifically targets the filesystem access controls implemented through the `--permission` flag mechanism, which is designed to restrict Node.js applications from accessing unauthorized file system resources. The flaw manifests as an improper boundary handling mechanism within the radix-tree implementation used to manage permission grants, allowing attackers to escalate their privileges beyond the intended scope of access permissions.
The technical implementation of this vulnerability stems from how Node.js processes filesystem path validation when multiple permission entries exist in the allowlist. When an attacker is granted access to a specific directory path such as `/app/data`, the radix-tree data structure used for path matching fails to properly enforce prefix boundaries during access checks. This misconfiguration allows malicious operations to traverse beyond the explicitly permitted path boundaries through clever manipulation of path components and directory traversal techniques. The flaw exists because the permission enforcement code does not adequately validate that access attempts remain within the originally granted permission scope.
Operational impact of this vulnerability is severe as it enables attackers to bypass filesystem access controls that are meant to protect sensitive data and system resources. An attacker who gains access to a single path within an application's allowed scope can potentially read or write to any other file system location that shares a common prefix with the granted access path. This could lead to unauthorized data exfiltration, system compromise, or privilege escalation attacks against applications running with restricted permissions. The vulnerability affects multiple active Node.js release lines including main, 22.x, 24.x, and 26.x, indicating it is a persistent flaw in the permission model implementation that has not been adequately addressed across the codebase.
Security implications extend beyond simple access control bypass to encompass potential data integrity violations and system confidentiality breaches. The vulnerability aligns with CWE-250: "Execute Code from Untrusted Input" and represents a privilege escalation issue that can be exploited through path manipulation techniques. From an ATT&CK framework perspective, this vulnerability maps to T1078: Valid Accounts and T1566: Phishing, as it enables attackers to leverage legitimate access patterns to gain unauthorized privileges. Organizations running Node.js applications with permission restrictions are particularly vulnerable, as the flaw can be exploited without requiring additional authentication or elevated privileges beyond what is already permitted.
Mitigation strategies should focus on immediate patching of affected Node.js versions and implementing additional runtime protections through application-level checks and monitoring. System administrators should review all existing permission configurations to identify potentially vulnerable setups and consider implementing more restrictive access controls at the operating system level. The recommended approach includes updating to patched versions of Node.js where available, implementing comprehensive logging of filesystem access attempts, and conducting security audits of existing permission models to identify potential boundary violations. Organizations should also consider deploying runtime application protection solutions that can detect and prevent malicious path traversal attempts that exploit this vulnerability.