EUVD-2026-18202Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Command injection prevention
MITRE ATT&CK
1 technique across 1 tactic: Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | While the CVSS score of 6.3 is moderate, multiple risk signals elevate practical concern. The CVSS vector confirms low attack complexity (AC:L) and network accessibility (AV:N), meaning authenticated users can easily exploit this without sophisticated techniques. The existence of publicly available exploit code (E:P per CVSS vector and confirmed POC availability) significantly increases real-world risk. However, the authentication requirement (PR:L) provides a critical control - attackers must first obtain valid credentials to the application. SSVC analysis favors patching: exploitation is confirmed possible (POC exists), the technical impact is high (command execution affecting confidentiality, integrity, and availability per C:L/I:L/A:L), though not automatable at scale without valid credentials. The absence of vendor response despite early notification via GitHub issue #15 suggests this remains unpatched in production deployments. |
| Exploit ScenarioDerived | An authenticated user with legitimate access to an efforthye fast-filesystem-mcp application crafts a request to the handleGetDiskUsage function containing shell metacharacters (e.g., backticks, pipes, command separators) in the input parameters. Due to insufficient input sanitization, the injected commands are executed with the privileges of the application process, allowing the attacker to read sensitive files, modify data, or establish reverse shells. Publicly released exploit code (available in the PDF at https://github.com/user-attachments/files/25822878/fast-filesystem-mcp_bug.pdf) lowers the skill barrier, making this accessible to opportunistic attackers who have obtained or compromised valid application credentials. |
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Alert meAnalysisAIv1 – Apr 02, 2026
Command injection in efforthye fast-filesystem-mcp up to version 3.5.1 allows authenticated remote attackers to execute arbitrary system commands via the handleGetDiskUsage function in src/index.ts. The vulnerability has a CVSS score of 6.3 (medium) with publicly available exploit code and no vendor patch released despite early notification through issue tracking. Exploitation requires valid authentication credentials but carries low attack complexity.
RemediationAI
No vendor-released patch identified at time of analysis. The project maintainer was notified early via GitHub issue (https://github.com/efforthye/fast-filesystem-mcp/issues/15) but has not responded with a fix. Organizations currently deploying fast-filesystem-mcp should immediately implement access controls to restrict usage to trusted, authenticated users only. Monitor the official GitHub repository (https://github.com/efforthye/fast-filesystem-mcp/) for security updates. As an interim mitigation, disable or restrict access to the handleGetDiskUsage endpoint if not operationally required, or implement web application firewall rules to detect and block command injection patterns in requests. Consider evaluating alternative filesystem implementations with active security maintenance. Users should avoid updating to versions 3.5.1 or earlier until a patched release becomes available.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in npm
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
The vulnerability stems from improper input validation in the handleGetDiskUsage function, classified under CWE-77 (Improper Neutralization of Special Elements used in a Command). The affected product is efforthye fast-filesystem-mcp, a fast filesystem implementation accessed via the Model Context Protocol (MCP). The command injection occurs when user-supplied input is concatenated into shell commands without proper escaping or parameterization. The CVSS vector (AV:N/AC:L/PR:L) indicates network-accessible attack surface with low attack complexity, but requires authenticated user privileges (PR:L). The E:P flag in the environmental metrics confirms public exploit availability.
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Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P
Primary rating from Vendor (VulDB) · only source for this CVE.
CVSS VectorVendor: VulDB
Lifecycle Timeline
4DescriptionCVE.org
A security flaw has been discovered in efforthye fast-filesystem-mcp up to 3.5.1. The affected element is the function handleGetDiskUsage of the file src/index.ts. Performing a manipulation results in command injection. The attack is possible to be carried out remotely. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
GitHub
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
OS command injection occurs when an application passes unsanitized user input directly into system shell commands.
Exploit-DB