CVE-2025-14135 is a stack-based buffer overflow vulnerability identified in several Linksys range extender models (RE6500, RE6250, RE6300, RE6350, RE7000, and RE9000) running specific 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 AP_get_wired_clientlist_setClientsName function within the mod_form.so module. Specifically, the function improperly processes the clientsname_0 argument, allowing an attacker to overflow the stack buffer. This flaw can be exploited remotely without requiring user interaction or elevated privileges, making it highly accessible to attackers. The overflow can lead to arbitrary code execution, compromising the device's confidentiality, integrity, and availability. The vendor was notified early but has not issued any patches or advisories, and no official remediation is currently available. A public exploit exists, increasing the risk of exploitation. The vulnerability has a CVSS 4.0 score of 8.7, indicating a high severity level due to its network attack vector, low attack complexity, no required privileges or user interaction, and high impact on all security properties. The affected devices are commonly used in home and small office networks, potentially serving as entry points for attackers to pivot into larger organizational networks.

For European organizations, this vulnerability poses a significant risk as Linksys range extenders are widely deployed in both residential and small business environments, which often connect to corporate networks. Exploitation could allow attackers to execute arbitrary code remotely, leading to device takeover, interception or manipulation of network traffic, and potential lateral movement within the network. This could result in data breaches, disruption of network services, and compromise of sensitive information. The lack of vendor response and patches increases the window of exposure. Organizations relying on these devices for network extension or Wi-Fi coverage may face increased risk of persistent threats or denial of service attacks. Additionally, compromised devices could be leveraged as part of botnets or for launching further attacks against critical infrastructure. The impact is heightened in sectors with stringent data protection requirements under GDPR, where unauthorized access or data leakage could lead to regulatory penalties.

Until official patches are released, European organizations should implement specific mitigations: 1) Immediately identify and inventory all affected Linksys devices within their environment. 2) Disable remote management interfaces on these devices to prevent external exploitation. 3) Segment the network to isolate vulnerable devices from critical infrastructure and sensitive data repositories. 4) Employ strict firewall rules to limit inbound and outbound traffic to and from these devices. 5) Monitor network traffic for unusual patterns or exploit attempts targeting the clientsname_0 parameter or related endpoints. 6) Consider replacing vulnerable devices with models from vendors that provide timely security updates. 7) Educate users about the risks of using unsupported or unpatched network equipment. 8) Regularly review and update network device firmware once patches become available. 9) Use intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability or exploit. 10) Coordinate with cybersecurity teams to prepare incident response plans specific to potential exploitation scenarios involving these devices.