CVE-2026-82766: SGA1000 OS Command Injection Vulnerability

CVE-2026-82766 Overview

CVE-2026-82766 is an OS command injection vulnerability [CWE-78] affecting the Contec SGA1000 industrial gateway. The flaw stems from improper neutralization of special elements passed to operating system commands. An authenticated attacker who can log in to the product can execute arbitrary OS commands on the underlying system. Successful exploitation grants command execution in the context of the device's operating system, potentially compromising confidentiality, integrity, and availability of the appliance.

Critical Impact
An authenticated remote attacker can execute arbitrary operating system commands on affected SGA1000 devices, leading to full compromise of the gateway.

Affected Products

Contec SGA1000
Refer to the Contec Security Information Document for affected firmware versions
Refer to JVN Security Advisory JVNVU99009004 for coordinated vendor advisory details

Discovery Timeline

2026-09-14 - CVE-2026-82766 published to the National Vulnerability Database (NVD)
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-82766

Vulnerability Analysis

The vulnerability resides in a command-processing path within the SGA1000 firmware that accepts user-supplied input and passes it to an operating system shell without adequate sanitization. An authenticated attacker supplies crafted input containing shell metacharacters such as ;, |, &, $(), or backticks. The device concatenates the input into a system command string and executes it via the OS shell. Because the injected commands run in the context of the SGA1000 firmware process, the attacker gains the same privileges as that process on the appliance. This is a Network attack vector requiring low privileges and no user interaction, enabling straightforward post-authentication compromise.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-78]. The affected code path constructs shell command strings by concatenating attacker-controlled parameters rather than using a safe execution API with argument arrays or applying strict allow-list input validation. Shell metacharacters therefore break out of the intended command context.

Attack Vector

Exploitation requires network access to the SGA1000 management interface and valid credentials for the product. Once authenticated, an attacker submits a request to a vulnerable endpoint containing shell metacharacters in a parameter that is subsequently passed to a system command. The injected payload is executed by the underlying shell. See the JVN Security Advisory JVNVU99009004 for coordinated disclosure details.

No verified public proof-of-concept code is available at the time of publication. Refer to vendor documentation for technical specifics.

Detection Methods for CVE-2026-82766

Indicators of Compromise

Unexpected child processes spawned by SGA1000 firmware services, particularly shell interpreters executing non-standard binaries.
Outbound network connections from the device to unfamiliar hosts following administrative sessions.
Configuration file changes, new user accounts, or scheduled tasks that were not created by authorized administrators.
Authentication log entries showing successful logins from unusual source IP addresses immediately preceding anomalous device behavior.

Detection Strategies

Inspect device management traffic for HTTP or API parameters containing shell metacharacters such as ;, |, &&, `, or $(.
Correlate authentication events with subsequent command execution on the gateway to identify suspicious operator sessions.
Baseline normal SGA1000 process activity and alert on deviations that could indicate command injection.

Monitoring Recommendations

Forward SGA1000 syslog and authentication events to a centralized SIEM for retention and correlation.
Enable and review audit logging on the management interface, focusing on administrative endpoints that accept parameters.
Monitor network segments that host the SGA1000 for unusual egress traffic patterns originating from the device.

How to Mitigate CVE-2026-82766

Immediate Actions Required

Apply the firmware update published by Contec as referenced in the Contec Security Information Document.
Rotate all credentials used to authenticate to the SGA1000 management interface.
Restrict management interface access to a dedicated administrative network or jump host.
Audit existing accounts on the device and remove any that are unnecessary or unrecognized.

Patch Information

Contec has published a security information document for this issue. Consult the Contec Security Information Document and JVN Security Advisory JVNVU99009004 for the fixed firmware version and update procedure applicable to your deployment.

Workarounds

Place the SGA1000 behind a firewall that restricts access to the management interface to a narrow allow-list of trusted source addresses.
Enforce strong, unique credentials and multi-factor controls on administrator accounts where the device or upstream infrastructure supports it.
Disable or block remote management access from untrusted networks until the firmware update can be applied.

bash

# Example iptables rule restricting SGA1000 management access to a trusted admin subnet
iptables -A INPUT -p tcp --dport 443 -s 10.10.20.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP