CVE-2026-82947 in SOEM
Summary
by MITRE • 10/26/2026
SOEM version 2.0.0 and earlier contains multiple vulnerabilities in frame processing where a malicious device can cause the master to read data outside allocated buffers. The software uses length and offset values from device messages without validating them against buffer sizes. This can cause the master to access invalid memory locations, potentially disclosing sensitive information or causing crashes.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability identified in SOEM version 2.0.0 and earlier represents a critical failure in input validation within the EtherCAT Open Master implementation. Specifically, the flaw resides in the frame processing logic where the software fails to rigorously validate length and offset values extracted from incoming device messages against the actual sizes of allocated memory buffers. This lack of boundary checking allows an attacker who can inject or manipulate network traffic on the EtherCAT bus to craft malicious frames that instruct the master controller to read data beyond the bounds of its designated memory regions. The root cause is a classic buffer over-read condition, where the application trusts external input without performing necessary sanity checks before accessing memory locations determined by those inputs.
From a technical perspective, this vulnerability aligns with CWE-126 Buffer Over-read and CWE-20 Improper Input Validation as defined in the Common Weakness Enumeration standard. When the master processes frames from connected slave devices or malicious actors posing as slaves, it utilizes the length and offset parameters to calculate memory addresses for data retrieval. Because these values are not constrained by the size of the buffer allocated for that specific operation, a crafted packet can specify an offset or length that extends past the end of the valid memory space. This results in the master reading arbitrary contents from adjacent memory locations, which may contain sensitive operational data, cryptographic keys, or other confidential information stored within the process control system's memory footprint.
The operational impact of this vulnerability is severe due to its potential for both confidentiality breaches and denial of service. By exploiting the over-read condition, an attacker can potentially exfiltrate sensitive industrial control system (ICS) data that resides in adjacent memory blocks, leading to significant intellectual property loss or compromise of security credentials. Furthermore, accessing invalid memory locations can trigger segmentation faults or other critical errors within the master application, causing it to crash unexpectedly. In a real-time industrial environment where deterministic communication is paramount, such crashes can lead to immediate production halts, safety system failures, and potential physical damage if connected machinery continues operating without proper control signals.
This attack vector maps directly to MITRE ATT&CK techniques related to reconnaissance and collection via network sniffing or manipulation of peripheral devices. An attacker positioned on the same Ethernet segment as the EtherCAT master can exploit this flaw by sending specially crafted frames that mimic legitimate device communications but contain malicious offset values. The lack of validation means there is no immediate detection mechanism within SOEM itself, making it difficult for standard intrusion prevention systems to identify the anomaly without deep packet inspection capabilities tailored to EtherCAT protocol semantics.
Mitigation strategies must focus on both software updates and network segmentation. The primary remediation is to upgrade SOEM to a version that includes proper bounds checking for all frame processing operations, ensuring that length and offset values are strictly validated against buffer sizes before any memory access occurs. In environments where immediate patching is not feasible, deploying the EtherCAT master behind an unidirectional gateway or implementing strict network segmentation can limit exposure to trusted devices only. Additionally, enabling deep packet inspection on industrial firewalls configured with specific EtherCAT signatures may help detect and block malformed frames attempting to exploit this vulnerability before they reach the master controller.