CVE-2026-82777: CONPROSYS PAC Series RCE Vulnerability

CVE-2026-82777 Overview

CVE-2026-82777 is an OS command injection vulnerability [CWE-78] affecting the CONPROSYS PAC Series from Contec. 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. Because CONPROSYS PAC devices are programmable automation controllers deployed in industrial environments, successful exploitation can affect the confidentiality, integrity, and availability of connected industrial processes.

Critical Impact
An authenticated remote attacker can execute arbitrary operating system commands on affected CONPROSYS PAC Series controllers, gaining full control of the device and any industrial process it manages.

Affected Products

Contec CONPROSYS PAC Series programmable automation controllers
Refer to the Contec Security Advisory Document for the specific model and firmware versions in scope
Coordinated advisory tracked as JVN Vulnerability Information JVNVU96551518

Discovery Timeline

2026-09-14 - CVE-2026-82777 published to NVD
2026-09-16 - Last updated in NVD database

Technical Details for CVE-2026-82777

Vulnerability Analysis

The CONPROSYS PAC Series exposes management functionality that constructs OS commands using attacker-controlled input without adequate sanitization. When an authenticated user submits crafted input containing shell metacharacters such as ;, |, &, or backticks, the input is concatenated into a command line and passed to the operating system shell. The shell interprets the injected metacharacters as command separators, allowing arbitrary commands to run in the context of the process handling the request. This process typically executes with elevated privileges on embedded industrial devices, giving the attacker broad control of the controller.

Root Cause

The root cause is improper neutralization of special elements used in an OS command [CWE-78]. The affected input handler fails to validate, escape, or reject shell metacharacters before invoking a system command. Safe alternatives such as parameterized process execution (for example, passing arguments as an array to execve-style APIs rather than through a shell) are not used.

Attack Vector

Exploitation requires network access to the device management interface and valid credentials. The attack complexity is low and no user interaction is needed. Once authenticated, an attacker sends a crafted request to the vulnerable endpoint with shell metacharacters embedded in a parameter that flows into an OS command. The injected payload executes with the privileges of the service handling the request, which on industrial controllers is commonly a privileged system account.

No public proof-of-concept exploit is available at the time of publication, and the issue is not listed in the CISA Known Exploited Vulnerabilities catalog. The EPSS probability is approximately 1.19% (66th percentile) as of 2026-09-18.

Detection Methods for CVE-2026-82777

Indicators of Compromise

Unexpected child processes spawned by the CONPROSYS PAC management service, such as /bin/sh, wget, curl, nc, or busybox.
Outbound network connections from the controller to unknown destinations, particularly on non-standard ports.
New or modified files in writable directories on the device, or unexpected changes to startup scripts.
Authentication log entries showing successful logins from unusual source IPs immediately preceding anomalous command activity.

Detection Strategies

Inspect HTTP or management-protocol requests to the CONPROSYS PAC interface for shell metacharacters (;, |, &, `, $() in parameters that were not previously expected to contain them.
Correlate authentication events with process-execution telemetry from any adjacent monitoring appliance to identify command execution that follows a login.
Alert on deviations from the controller's baseline process tree, since embedded systems typically run a small, stable set of processes.

Monitoring Recommendations

Forward device syslog and authentication logs to a centralized SIEM for retention and correlation.
Monitor north-south and east-west traffic to and from CONPROSYS PAC devices using network detection tooling with ICS protocol awareness.
Track failed and successful logins to the management interface and alert on brute-force patterns or logins from unauthorized network segments.

How to Mitigate CVE-2026-82777

Immediate Actions Required

Apply the firmware updates published by Contec in the Contec Security Advisory Document as soon as they are available for your model.
Restrict network access to the CONPROSYS PAC management interface to a dedicated, isolated OT management VLAN.
Rotate credentials on affected controllers and remove any unused or default accounts.
Audit recent authentication and command activity on exposed devices for signs of prior exploitation.

Patch Information

Contec has published a security advisory covering CVE-2026-82777. Refer to the Contec Security Advisory Document and the coordinated JVN advisory JVNVU96551518 for affected model and firmware version details, along with the vendor's recommended fixed versions and update procedure.

Workarounds

Block access to the device management interface from untrusted networks using firewall or ACL rules until firmware is updated.
Enforce strong, unique passwords for all accounts that can authenticate to the controller, and disable accounts that are not required.
Place CONPROSYS PAC devices behind a jump host or VPN that enforces multi-factor authentication for operator access.
Continuously monitor authentication attempts and management-plane traffic for anomalies while a patch window is scheduled.