CVE-2025-9251 is a high-severity stack-based buffer overflow vulnerability affecting multiple Linksys range extender models, including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000, across firmware versions 1.0.013.001, 1.0.04.001, 1.0.04.002, 1.1.05.003, and 1.2.07.001. The vulnerability resides in the function sta_wps_pin within the /goform/sta_wps_pin endpoint, where improper handling of the Ssid argument allows an attacker to overflow the stack buffer. This flaw can be exploited remotely without requiring user interaction or prior authentication, making it particularly dangerous. The CVSS 4.0 base score is 8.7, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction needed. The overflow could enable remote code execution or cause denial of service, potentially allowing attackers to take full control of the affected device or disrupt network connectivity. Despite early notification, Linksys has not responded or issued patches, and a public exploit has been released, increasing the risk of active exploitation. The vulnerability affects the core functionality of wireless range extenders, which are commonly deployed in enterprise and home networks to improve Wi-Fi coverage. Successful exploitation could lead to network compromise, lateral movement, or interception of sensitive data passing through these devices.

For European organizations, this vulnerability poses a significant risk to network security and operational continuity. Many enterprises and small-to-medium businesses rely on Linksys range extenders to maintain reliable wireless connectivity across offices and facilities. Exploitation could allow attackers to gain unauthorized access to internal networks, intercept or manipulate traffic, and disrupt wireless services, impacting business operations and data confidentiality. Critical infrastructure sectors such as finance, healthcare, and government agencies using these devices could face heightened risks of espionage or sabotage. Additionally, the lack of vendor response and available patches means organizations must rely on alternative mitigations, increasing operational burden. The public availability of exploits raises the likelihood of widespread attacks, including opportunistic scanning and automated exploitation campaigns targeting vulnerable devices across Europe.

Given the absence of official patches, European organizations should immediately implement compensating controls. These include isolating affected Linksys extenders on segmented VLANs or dedicated subnets to limit lateral movement if compromised. Network administrators should disable WPS functionality if possible, as the vulnerability is related to the WPS PIN handling. Monitoring network traffic for unusual activity or exploitation attempts targeting /goform/sta_wps_pin endpoints is critical. Employing intrusion detection/prevention systems (IDS/IPS) with updated signatures can help detect and block exploit attempts. Organizations should consider replacing vulnerable devices with models from vendors providing timely security updates. Additionally, restricting remote management access to trusted IPs and enforcing strong network access controls can reduce exposure. Regular network device inventories and firmware version audits will help identify and prioritize vulnerable units for remediation or replacement.