CVE-2025-57685 is a critical command injection vulnerability identified in several LB-Link router models, including BL-AC2100_AZ3 V1.0.4, BL-WR4000 v2.5.0, BL-WR9000_AE4 v2.4.9, BL-AC1900_AZ2 v1.0.2, BL-X26_AC8 v1.2.8, and BL-LTE300_DA4 V1.2.3. The flaw resides in the /goform/set_serial_cfg web interface, which improperly sanitizes input parameters, allowing unauthenticated remote attackers to inject arbitrary commands. Exploitation grants attackers the highest privilege level on the device, enabling full control over router functions, including configuration changes, network traffic interception, and potential pivoting to internal networks. The vulnerability is classified under CWE-77 (Improper Neutralization of Special Elements used in a Command), indicating command injection risks. The CVSS v3.1 score is 8.8 (High), reflecting the vulnerability's ease of remote exploitation without authentication or user interaction and its severe impact on confidentiality, integrity, and availability. Although no public exploits are currently reported, the vulnerability's characteristics suggest it could be weaponized rapidly. The lack of available patches at the time of disclosure increases the urgency for interim mitigations. This vulnerability poses a significant risk to organizations relying on these LB-Link routers, especially in environments where these devices serve as critical network gateways or are exposed to untrusted networks.

For European organizations, exploitation of CVE-2025-57685 could lead to complete compromise of affected routers, resulting in unauthorized access to internal networks, interception of sensitive data, and disruption of network services. Attackers gaining control over routers can manipulate traffic flows, deploy malware, or establish persistent backdoors, severely impacting operational continuity and data confidentiality. Critical sectors such as finance, healthcare, and government agencies using these routers may face heightened risks of espionage, data breaches, and service outages. The vulnerability's remote and unauthenticated nature increases the attack surface, particularly for organizations with routers exposed to the internet or poorly segmented networks. Additionally, supply chain and managed service providers using these devices could inadvertently propagate risks to multiple clients. The absence of known exploits currently provides a narrow window for proactive defense, but the high severity score indicates that successful exploitation would have widespread and severe consequences.

1. Immediately inventory all LB-Link router models within the organization to identify affected devices. 2. Monitor LB-Link vendor communications for official firmware updates addressing CVE-2025-57685 and apply patches promptly upon release. 3. Until patches are available, restrict access to the /goform/set_serial_cfg interface by implementing network-level controls such as firewall rules or access control lists to block external and unauthorized internal access. 4. Employ network segmentation to isolate router management interfaces from general user networks and the internet. 5. Enable logging and continuous monitoring for unusual router behavior or unexpected configuration changes indicative of exploitation attempts. 6. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures targeting command injection attempts on LB-Link routers. 7. Educate IT and security teams about the vulnerability specifics to enhance incident response readiness. 8. For managed service providers, communicate with clients about the vulnerability and coordinate mitigation efforts. 9. Review and harden router configurations, disabling unnecessary services and interfaces to reduce attack vectors. 10. Implement multi-factor authentication and strong password policies for router management interfaces where applicable to reduce risk from other attack vectors.