CVE-2026-25933: Arduino App Lab RCE Vulnerability

CVE-2026-25933 Overview

CVE-2026-25933 is a command injection vulnerability [CWE-78] in Arduino App Lab, a cross-platform integrated development environment (IDE) for developing Arduino Apps. The flaw resides in the Terminal component of the arduino-app-lab application. The application fails to sanitize device metadata received over a hardware connection, specifically the _info.Serial and _info.Address fields. An attacker who controls a tampered Arduino board can inject shell metacharacters into these fields. When the host processes the device information to establish a terminal session, the injected payload executes with the privileges of the user running arduino-app-lab. The vulnerability is fixed in version 0.4.0.

Critical Impact

Attackers with physical access to a tampered Arduino board can execute arbitrary commands on the host system at user privilege, compromising confidentiality, integrity, and availability of the developer workstation.

Affected Products

• Arduino App Lab versions prior to 0.4.0
• Cross-platform installations (Windows, macOS, Linux) running vulnerable releases
• Developer workstations that connect to untrusted or shared Arduino hardware

Discovery Timeline

• 2026-02-12 - CVE-2026-25933 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-25933

Vulnerability Analysis

The vulnerability is an OS command injection flaw in the Terminal component of Arduino App Lab. When a board is connected, the application enumerates identifying attributes to establish a terminal session. Two of these attributes, _info.Serial and _info.Address, are sourced directly from the connected hardware. The application passes these values to a host shell context without validation or escaping of metacharacters such as ;, |, &, backticks, or $().

Because the device-supplied strings reach a shell interpreter, an attacker who controls a board's reported metadata can break out of the intended command and execute arbitrary operating system commands. Code runs in the security context of the local user running arduino-app-lab, which on developer workstations typically includes access to source code, signing keys, and cloud credentials.

Root Cause

The root cause is insufficient input validation of trust-boundary data crossing from the hardware layer into the host application. The Terminal component treated _info.Serial and _info.Address as trusted metadata rather than untrusted external input. Neither allow-list validation nor argument-array invocation was applied before the values reached the shell.

Attack Vector

Exploitation requires physical access to a previously tampered board and user interaction to initiate a terminal session. A prepared microcontroller advertises crafted USB descriptor or serial identification strings containing shell metacharacters. When a developer plugs in the board and opens the Terminal view in Arduino App Lab, the malicious payload embedded in the Serial or Address field is interpreted by the host shell and executed.

Refer to the GitHub Security Advisory GHSA-3652-939f-f7g4 for vendor technical details.

Detection Methods for CVE-2026-25933

Indicators of Compromise

• Unexpected child processes spawned by the arduino-app-lab process, particularly shell interpreters such as bash, sh, cmd.exe, or powershell.exe.
• Outbound network connections initiated shortly after a USB device connection event on a developer workstation.
• New or modified files in user profile directories, SSH key stores, or credential caches following an Arduino board connection.

Detection Strategies

• Monitor process lineage where arduino-app-lab is the parent of shell or scripting interpreters with unusual command-line arguments.
• Correlate USB device attachment events with subsequent process creation and network activity on the same host.
• Inspect application logs for _info.Serial or _info.Address values that contain shell metacharacters or non-printable bytes.

Monitoring Recommendations

• Enable command-line and process-creation auditing on developer endpoints to capture full argument strings.
• Alert on Arduino App Lab versions below 0.4.0 reported by software inventory tools.
• Track USB device enumeration events and flag boards reporting abnormally long or special-character-laden identifiers.

How to Mitigate CVE-2026-25933

Immediate Actions Required

• Upgrade Arduino App Lab to version 0.4.0 or later on all developer workstations.
• Restrict connection of Arduino boards to trusted, organization-controlled hardware only.
• Audit recent USB connection events on systems running vulnerable versions for signs of tampered boards.

Patch Information

Arduino published the fix in release 0.4.0. Download and installation details are available at the GitHub Release v0.4.0 page. The patch enforces strict validation on the _info.Serial and _info.Address fields before they are used to construct terminal sessions.

Workarounds

• Avoid connecting Arduino boards of unknown provenance to workstations running vulnerable versions of App Lab.
• Run arduino-app-lab under a least-privilege user account that lacks access to sensitive credentials or source repositories.
• Disable USB device access on shared or kiosk systems where the IDE must remain installed until patching is complete.

# Configuration example: verify installed version and upgrade
arduino-app-lab --version
# Upgrade to fixed release 0.4.0 or later via the official GitHub release page