CVE-2026-5327: fast-filesystem-mcp Command Injection Vulnerability
Summary
CVE-2026-5327: fast-filesystem-mcp is vulnerable to command injection through handleGetDiskUsage function. Affects fast-filesystem-mcp versions < 3.5.0. No fix is published. How to fix ↓
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Background
fast-filesystem-mcp is an npm package designed to facilitate efficient disk usage management in Node.js applications. It provides functionalities to retrieve and manage disk usage statistics. However, versions up to 3.5.1 are vulnerable to a command injection flaw, which can be exploited remotely, potentially compromising the security of applications utilizing this package.
Vulnerability Detail
The vulnerability arises from the handleGetDiskUsage function located in src/index.ts of the fast-filesystem-mcp package. An attacker can manipulate input to execute arbitrary commands on the server, leading to unauthorized access or data manipulation. This flaw is classified under CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component), and it poses a significant risk as it can be exploited remotely, allowing attackers to execute commands without authentication.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a temporary workaround, you can restrict access to the handleGetDiskUsage function by implementing input validation and sanitization to prevent malicious input from being processed. However, this is not a complete solution and updating the package is strongly recommended.
Conclusion
The fast-filesystem-mcp package has a critical command injection vulnerability that can be exploited remotely. It is essential to update to the latest version to protect your applications from potential attacks. Implementing workarounds can provide temporary relief, but updating is the best long-term solution.
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FAQ
The vulnerability is a command injection flaw that allows attackers to execute arbitrary commands on the server.
Versions up to 3.5.0 of fast-filesystem-mcp are affected by this vulnerability.
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The CVSS score of this vulnerability is 6.3, indicating a moderate level of risk.
If immediate updating is not possible, implement input validation and sanitization as a temporary workaround to mitigate the risk.
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