CVE-2026-58039 in Node.js
Summary
by MITRE • 07/31/2026
A flaw in Node.js Permission Model enforcement allows process.report writes (and overwrites) files outside --allow-fs-write paths.
This can lead to confidentiality impact or bypass of the intended security boundary under affected configurations.
This vulnerability affects Node.js **22.x**, **24.x**, and **26.x**.
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Analysis
by VulDB Data Team • 07/31/2026
The vulnerability in Node.js permission model represents a critical flaw in the enforcement of file system write restrictions that undermines fundamental security boundaries designed to protect applications from unauthorized file operations. This issue specifically targets the process.report functionality which is intended to provide diagnostic information about running Node.js processes, but can be exploited to write files outside of explicitly allowed paths through improper validation of file system permissions.
The technical implementation flaw stems from insufficient validation within Node.js's permission model where the --allow-fs-write flag configuration does not properly restrict the process.report API from creating or overwriting files in directories beyond the specified allowed paths. This occurs because the permission enforcement mechanism fails to adequately sanitize file paths when process.report attempts to write diagnostic data, allowing malicious actors to bypass intended security constraints through crafted file system operations.
The operational impact of this vulnerability extends beyond simple privilege escalation as it can result in significant confidentiality breaches and complete bypass of security boundaries that administrators have configured. Attackers can leverage this flaw to overwrite critical system files, inject malicious code into applications, or exfiltrate sensitive data from locations that should otherwise be protected by the permission model. The vulnerability is particularly concerning because it operates at the core of Node.js's security architecture, affecting process-level diagnostics that are commonly used in production environments.
This vulnerability aligns with CWE-276 which describes inadequate privileges and permissions, and maps to ATT&CK technique T1059.006 for command and scripting interpreter usage where attackers can manipulate file system operations through legitimate diagnostic APIs. The affected versions Node.js 22.x, 24.x, and 26.x all share this permission model implementation flaw that stems from improper path validation during file system write operations.
Organizations should immediately implement mitigations including restricting the use of process.report functionality in production environments, ensuring that --allow-fs-write paths are strictly limited to absolute minimum required directories, and monitoring for unusual file system write patterns. Additionally, administrators should consider disabling process.report functionality entirely unless absolutely required for debugging purposes, as this API can be exploited even when other security controls are properly configured. The most effective long-term solution involves upgrading to patched versions of Node.js where the permission model enforcement has been corrected to properly validate all file system operations regardless of API source.
The vulnerability demonstrates how seemingly benign diagnostic functionality can become a critical security risk when permission models fail to account for all possible code paths and API interactions within the runtime environment. This flaw underscores the importance of comprehensive security testing that includes not just direct API usage but also indirect exploitation vectors through legitimate system components. Organizations should conduct thorough audits of their Node.js applications to identify any usage patterns that might expose them to this vulnerability, particularly in containerized environments where process reporting is commonly enabled for operational monitoring purposes.
Security teams must also consider implementing additional monitoring controls specifically designed to detect unauthorized file system operations that bypass standard permission models, as traditional security controls may not adequately detect this type of privilege escalation. The remediation strategy should include not only patching affected versions but also establishing baseline configurations that prevent the use of potentially dangerous APIs in production environments while maintaining operational visibility through alternative security monitoring approaches.