CVE-2025-67366 identifies a critical path traversal vulnerability in version 0.5.8 of the filesystem-mcp server, specifically within its read_content tool. The vulnerability arises from a flawed path validation mechanism where the resolvePath function validates the file path before resolving symbolic links (symlinks). However, the underlying file reading function, fs.readFile, automatically resolves symlinks during file access. This discrepancy allows an attacker to place or leverage symlinks inside the allowed directory that point to files outside the permitted directory tree. Because the validation step does not account for symlink resolution, the attacker can bypass directory restrictions and read arbitrary files on the server's filesystem. This can lead to unauthorized disclosure of sensitive information, such as configuration files, credentials, or other protected data. The vulnerability does not require authentication or user interaction, increasing its risk. Although no public exploits are currently known, the flaw's nature and ease of exploitation make it a significant threat. The vulnerability affects all deployments running the vulnerable version of filesystem-mcp, particularly those exposing the read_content tool to untrusted users or networks. The lack of a patch link indicates that remediation may require vendor updates or custom mitigations. Organizations relying on this software for file content access should prioritize addressing this issue to prevent data breaches.

For European organizations, exploitation of CVE-2025-67366 could result in unauthorized access to sensitive files, leading to confidentiality breaches and potential exposure of critical business or personal data. This can undermine trust, lead to regulatory non-compliance (e.g., GDPR violations), and cause operational disruptions if sensitive configuration or credential files are disclosed. Sectors such as finance, healthcare, government, and critical infrastructure that handle sensitive or regulated data are particularly at risk. The vulnerability's ability to bypass directory restrictions without authentication means attackers could exploit it remotely if the MCP server is exposed to untrusted networks. This elevates the risk of targeted attacks or opportunistic scanning by threat actors. Additionally, the exposure of internal files could facilitate further attacks, such as privilege escalation or lateral movement within networks. The absence of known exploits currently provides a window for proactive mitigation, but the critical nature of the flaw demands urgent attention to prevent potential future exploitation.

To mitigate CVE-2025-67366, organizations should first verify if they are running filesystem-mcp version 0.5.8 or any vulnerable variant. Immediate steps include restricting access to the MCP server and the read_content tool to trusted users and networks only, ideally behind firewalls or VPNs. Implement strict input validation that resolves symlinks before performing path validation to ensure that file access is confined to authorized directories. If vendor patches become available, apply them promptly. In the absence of official patches, consider deploying custom wrappers or filters that sanitize and canonicalize file paths before access. Conduct thorough audits of filesystem permissions and symlink usage to detect and remove any malicious or unintended symlinks. Monitor logs for unusual file access patterns indicative of exploitation attempts. Finally, incorporate this vulnerability into incident response plans and ensure staff are aware of the risk and mitigation procedures.