CVE-2026-27476 is an OS command injection vulnerability identified in Bixat's RustFly product, specifically version 2.0.0. The vulnerability resides in the remote UI control mechanism that listens on UDP port 5005 and processes hex-encoded instructions. Due to improper neutralization of special elements in these instructions, the system fails to sanitize input properly, allowing attackers to inject arbitrary OS commands. This flaw enables unauthenticated remote attackers to execute arbitrary commands on the affected system by sending specially crafted hex-encoded payloads over UDP. The attack surface is significant because UDP port 5005 is open and listening, and no authentication or user interaction is required to exploit the vulnerability. Potential malicious activities include executing system commands, establishing reverse shells, and gaining full control over the compromised system. The vulnerability has been assigned a CVSS 4.0 base score of 9.3, indicating critical severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the nature of the vulnerability and exposed UDP service make it a prime target for attackers once exploit code becomes available. The lack of patches at the time of reporting necessitates immediate mitigation efforts by affected organizations. This vulnerability highlights the risks of insufficient input validation in network-facing services and the importance of secure coding practices, especially for remote control interfaces.

The impact of CVE-2026-27476 is severe for organizations worldwide using Bixat RustFly 2.0.0. Successful exploitation allows attackers to execute arbitrary commands remotely without authentication, leading to full system compromise. This can result in data breaches, unauthorized access to sensitive information, disruption of services, and the establishment of persistent backdoors such as reverse shells. Critical infrastructure, industrial control systems, and enterprise environments relying on RustFly for remote management are particularly at risk. The vulnerability compromises confidentiality, integrity, and availability simultaneously, potentially causing operational downtime, financial losses, and reputational damage. Since the attack vector is network-based over UDP and requires no user interaction, automated exploitation attempts could rapidly spread in vulnerable environments. The absence of known exploits currently provides a window for proactive defense, but the critical severity score underscores the urgency for mitigation to prevent future attacks.

1. Immediately restrict or block inbound UDP traffic on port 5005 at network perimeter firewalls and internal segmentation points to prevent unauthorized access to the RustFly remote UI control interface. 2. Monitor network traffic on UDP port 5005 for anomalous or unexpected hex-encoded payloads indicative of exploitation attempts. 3. Apply vendor-provided patches or updates as soon as they become available to address the input sanitization flaw in RustFly 2.0.0. 4. If patching is not immediately possible, consider disabling the remote UI control feature or the UDP service on port 5005 to eliminate the attack surface. 5. Conduct thorough audits of systems running RustFly to detect any signs of compromise, including unusual command executions or reverse shell activity. 6. Implement strict input validation and sanitization controls in development processes for remote management interfaces to prevent similar vulnerabilities. 7. Employ intrusion detection/prevention systems (IDS/IPS) with signatures tailored to detect exploitation attempts targeting this vulnerability. 8. Educate network and security teams about this vulnerability to ensure rapid response and containment in case of attempted exploitation.