CVE-2025-47203 is a medium severity vulnerability identified in the Dropbear SSH Project, specifically affecting the dbclient component in versions prior to 2025.88. The vulnerability is classified as CWE-78, which corresponds to improper neutralization of special elements used in an OS command, commonly known as OS command injection. The root cause of this vulnerability lies in the way dbclient handles the hostname argument: it uses a shell to process this input without adequately sanitizing or neutralizing special characters. This allows an attacker who can supply an untrusted hostname argument to inject arbitrary OS commands that the shell will execute. The CVSS v3.1 base score is 4.5, reflecting a medium severity level. The vector string CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N indicates that the attack requires local access (AV:L), high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The scope is changed (S:C), meaning the vulnerability affects resources beyond the vulnerable component. The impact on confidentiality and integrity is low (C:L/I:L), with no impact on availability (A:N). There are no known exploits in the wild at the time of publication, and no patch links have been provided yet. The vulnerability was reserved on May 2, 2025, and published on May 7, 2025. Dropbear SSH is a lightweight SSH server and client implementation commonly used in embedded systems and IoT devices, which often have limited resources and run Linux-based operating systems. The vulnerability could be exploited by an attacker with local access to the system or the ability to influence the hostname argument passed to dbclient, potentially leading to unauthorized command execution and partial compromise of system confidentiality and integrity.

For European organizations, the impact of CVE-2025-47203 depends largely on the deployment of Dropbear SSH within their infrastructure, particularly in embedded devices, network appliances, or IoT environments. Many industrial control systems, telecommunications equipment, and network devices in Europe utilize lightweight SSH implementations like Dropbear due to resource constraints. Exploitation of this vulnerability could allow attackers with local access or the ability to manipulate hostname inputs to execute arbitrary commands, potentially leading to unauthorized data access, modification, or lateral movement within networks. While the vulnerability does not directly affect availability, the integrity and confidentiality impacts could facilitate further attacks or data breaches. Given the prevalence of embedded systems in critical infrastructure sectors such as energy, manufacturing, and transportation across Europe, exploitation could have cascading effects on operational technology environments. Additionally, the changed scope of the vulnerability suggests that exploitation could affect components beyond the immediate vulnerable process, increasing risk. However, the requirement for local access and high attack complexity somewhat limits the attack surface, reducing the likelihood of widespread exploitation in typical enterprise environments. Nonetheless, organizations relying on Dropbear SSH in sensitive or critical systems should consider this vulnerability a significant risk.

1. Immediate upgrade: Organizations should monitor the Dropbear SSH Project for the release of version 2025.88 or later, which addresses this vulnerability, and plan to upgrade affected systems promptly. 2. Input validation: Until patches are available, implement strict input validation and sanitization on any interfaces or scripts that pass hostname arguments to dbclient to prevent injection of malicious shell commands. 3. Access control: Restrict local access to systems running Dropbear SSH to trusted personnel only, and enforce strong authentication and authorization policies to reduce the risk of unauthorized exploitation. 4. Network segmentation: Isolate embedded devices and IoT systems running Dropbear SSH from critical network segments to limit potential lateral movement in case of compromise. 5. Monitoring and detection: Deploy host-based intrusion detection systems (HIDS) and monitor logs for unusual command execution patterns or anomalies related to dbclient usage. 6. Configuration review: Review and harden SSH client configurations to minimize exposure, including disabling unnecessary features or options that could be exploited via hostname arguments. 7. Incident response readiness: Prepare incident response plans that include scenarios involving local command injection on embedded devices to ensure rapid containment and remediation.