CVE-2026-82785 in Remote IO Coupler Unit
Summary
by MITRE • 09/14/2026
Stack-based buffer overflow vulnerability exists in Remote I/O Coupler Unit (Server Type) CPSN-MCB271-*. Receiving a specially crafted request created and sent by a remote attacker may cause a denial-of-service (DoS) condition.
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Analysis
by VulDB Data Team • 09/14/2026
The identified security flaw represents a critical stack-based buffer overflow vulnerability located within the Remote I/O Coupler Unit, specifically affecting models designated as CPSN-MCB271-*. This type of memory corruption error typically arises when software fails to properly validate the length or boundaries of input data before copying it into a fixed-size buffer allocated on the call stack. In this specific context, the vulnerability is triggered by receiving a specially crafted network request from a remote attacker. The lack of rigorous bounds checking allows an external entity to write more data than the buffer can hold, thereby overwriting adjacent memory locations that are critical for program execution flow or system stability.
From a technical perspective, stack-based buffer overflows exploit the way modern operating systems manage function calls and local variables in memory. When the oversized request is processed by the device's firmware, the excess data spills beyond the allocated buffer space into neighboring areas of the stack. This can overwrite return addresses, saved frame pointers, or other control structures that dictate where the program should resume execution after a function completes. While the immediate reported consequence is a denial-of-service condition, such memory corruption vulnerabilities often carry the potential for arbitrary code execution if an attacker can precisely manipulate the overwritten data to redirect instruction flow to malicious shellcode. However, in many embedded industrial devices like this coupler unit, security mitigations such as stack canaries or non-executable stacks may limit exploitation to causing a crash rather than full remote code execution.
The operational impact of this vulnerability is significant for environments relying on the CPSN-MCB271-* series for automated control processes. A successful exploit results in a denial-of-service, which manifests as the device becoming unresponsive or crashing entirely. In an industrial automation context, where continuous operation and real-time data exchange are paramount, such instability can lead to production halts, loss of telemetry data, or unsafe states if safety interlocks fail due to the crash. The fact that this vulnerability is remotely exploitable means it does not require physical access or prior authentication on the target system, significantly increasing its risk profile in networked industrial environments where these devices are often connected to broader control networks.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-120, which classifies buffer copies without checking size limits as a fundamental programming error leading to memory corruption. Furthermore, from an offensive security perspective, the exploitation technique falls under MITRE ATT&CK techniques related to Denial of Service and potentially Command and Control if the crash is used to disrupt monitoring systems or facilitate lateral movement by taking down critical infrastructure nodes. The ability for a remote attacker to trigger this condition via crafted network packets highlights a deficiency in input validation mechanisms within the device's communication stack, particularly regarding how it handles incoming requests from external sources without sufficient sanitization of payload sizes.
To mitigate this risk and protect industrial assets, immediate action is required at both the infrastructure and firmware levels. The most effective remediation involves applying vendor-provided software patches or firmware updates that address the buffer overflow by implementing strict input validation and bounds checking for all incoming requests processed by the Remote I/O Coupler Unit. Until such patches are applied, network segmentation strategies should be employed to isolate these devices from untrusted networks. This includes placing them behind firewalls with deep packet inspection capabilities configured to block malformed packets or unusually large payloads that match the characteristics of the exploit vector. Additionally, restricting access to management interfaces and disabling unnecessary services can reduce the attack surface available to potential adversaries seeking to trigger this denial-of-service condition.