CVE-2026-5327Public exploitNetwork attack vector

Authenticated command execution via shell-interpolated path

Published Apr 2, 2026 · Updated Apr 2, 2026

Command injection in efforthye fast-filesystem-mcp 3.5.0 and 3.5.1 allows remote authenticated users to execute host commands. The handleGetDiskUsage function interpolates a client-supplied path into a command string passed to child_process.execAsync, so shell metacharacters become commands. Access to invoke an MCP tool is required, and injected commands run with the MCP server process's privileges.

CVSS severity6.3
Medium
EPSS probability1.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in efforthye fast-filesystem-mcp 3.5.0 and 3.5.1 allows remote authenticated users to execute host commands. The handleGetDiskUsage function interpolates a client-supplied path into a command string passed to child_process.execAsync, so shell metacharacters become commands. Access to invoke an MCP tool is required, and injected commands run with the MCP server process's privileges.

The record

CVE
CVE-2026-5327
Published
Apr 2, 2026
Updated
Apr 2, 2026
Vendor
efforthye
Product
fast-filesystem-mcp
Classifications
CWE-77, CWE-74, T1059
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 2, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 2, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.5.0
  2. Affected versionversion=3.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

efforthye · fast-filesystem-mcpversion=3.5.0; version=3.5.1

Published CVSS scores

2.1VulDBCVSS: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
6.3VulDBCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
6.5VulDBAV:N/AC:L/Au:S/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
T1059Command and Scripting Interpreter

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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