CVE-2026-117573

hagent hardware MCP tools interpolate command arguments

masc-ucsc · hagent Arduino and ESP32 MCP tools

First documented disclosure · Review checkpoint

Summary

Crafted hardware-tool arguments could execute an unintended command on the MCP host.

Severity and exploitation evidence

High · 8.5/10 · CVSS 4.0. Severity source.

Exploitation not established: The reviewed sources describe a vulnerability and demonstration, not established malicious exploitation.

Technical severity is not a measure of observed attacks or of risk to your deployment. Attempts, demonstrations, and successful compromise retain the qualifications in the source.

How the weakness works

Caller-supplied args are appended to Arduino CLI and ESP-IDF shell command strings.

Conditions required

Ability to supply or influence an affected MCP invocation.

Potential impact

Command execution with the MCP process permissions and access to its files.

Affected versions and configurations

Through commit 761eec627a1e6fb128a2a8ce9245aa595cc2f7af.

Fix and mitigation status

No fixed version established in the reviewed sources.

Practical next steps

Disable affected tools until a verified fix; use argument arrays and restrict permitted subcommands.

Operating lesson

Giving an agent a tool argument must not silently grant it a general shell.

Evidence and limits

The unchanged October 24 issue predates October 27 assignment. No malicious exploitation or compromised device population is established.

Sources