CVE-2026-25817 in Ewon Flexy
Summary
by MITRE • 03/13/2026
HMS Networks Ewon Flexy with firmware before 15.0s4, Cosy+ with firmware 22.xx before 22.1s6, and Cosy+ with firmware 23.xx before 23.0s3 have improper neutralization of special elements used in an OS command allowing remote code execution by attackers with low privilege access on the gateway, provided the attacker has credentials.
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Analysis
by VulDB Data Team • 03/20/2026
The vulnerability identified as CVE-2026-25817 affects HMS Networks Ewon Flexy devices and Cosy+ series gateways across multiple firmware versions, presenting a critical security risk through improper input validation in operating system command execution. This vulnerability resides in the command injection mechanism where the system fails to properly sanitize user-supplied input before incorporating it into OS commands, creating a pathway for malicious actors to execute arbitrary code on affected devices. The flaw specifically manifests when the system processes user credentials and subsequently constructs OS commands without adequate neutralization of special characters that could alter command execution flow.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization practices within the gateway's command processing pipeline. When legitimate users provide credentials through the system interface, the firmware fails to properly escape or filter special characters that could be interpreted by the underlying operating system as command separators, operators, or injection points. This weakness allows an attacker with low privilege credentials to craft malicious input that, when processed, results in arbitrary code execution with the privileges of the affected service account. The vulnerability operates at the intersection of CWE-77 and CWE-88, representing both command injection and improper neutralization of special elements in command contexts.
From an operational perspective, this vulnerability creates a significant risk for industrial control systems and IoT deployments that rely on HMS Networks gateways for network connectivity and data management. Attackers can leverage this weakness to execute arbitrary commands on the device, potentially leading to complete system compromise, data exfiltration, or disruption of critical industrial processes. The requirement for only low privilege credentials to exploit this vulnerability means that insiders or attackers who have gained minimal access can escalate their privileges and gain full control over the affected gateway. This risk is particularly concerning in industrial environments where these devices often serve as critical communication points between field devices and enterprise networks, potentially serving as entry points for broader network infiltration.
The exploitation of this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to command and control operations and privilege escalation. Attackers can use this weakness to establish persistent access through the execution of malicious payloads, potentially installing backdoors or malware that can maintain access even after initial compromise. The remote execution capability means that attackers do not require physical access to the device, allowing for exploitation from external network locations. Organizations should implement immediate firmware updates to address the vulnerability, while also establishing network segmentation controls to limit the potential impact of successful exploitation. Additional mitigations include implementing network access controls, monitoring for suspicious command execution patterns, and maintaining detailed audit logs of user activities on affected devices. The vulnerability highlights the importance of input validation and proper security coding practices in embedded systems, particularly those operating in critical infrastructure environments where the consequences of compromise can be severe and far-reaching.