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, specifically in firmware versions 1.0.013.001, 1.0.04.001, 1.0.04.002, 1.1.05.003, and 1.2.07.001. The flaw resides in the sta_wps_pin function within the /goform/sta_wps_pin endpoint, where improper handling of the Ssid argument allows an attacker to overflow the stack buffer. This vulnerability can be exploited remotely without user interaction or prior authentication, making it particularly dangerous. The CVSS 4.0 score of 8.7 reflects its high impact, with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Exploitation could lead to arbitrary code execution, complete device compromise, or denial of service. Despite early notification, Linksys has not responded or issued patches, and while no exploits are currently known in the wild, a public exploit has been released, increasing the risk of imminent attacks. This vulnerability threatens the security and stability of affected devices, which often serve as critical network infrastructure components in both home and enterprise environments.

For European organizations, this vulnerability poses a significant risk to network security and operational continuity. Linksys range extenders are widely used to improve wireless coverage in offices, retail locations, and industrial sites. Successful exploitation could allow attackers to gain unauthorized control over these devices, enabling interception or manipulation of network traffic, lateral movement within corporate networks, or disruption of wireless connectivity. This could lead to data breaches, loss of sensitive information, and operational downtime. The absence of vendor patches exacerbates the threat, forcing organizations to rely on mitigations or device replacement. Given the remote and unauthenticated nature of the exploit, attackers could target vulnerable devices en masse, potentially impacting critical infrastructure and services. The high confidentiality, integrity, and availability impacts mean that both data theft and service disruption are realistic outcomes, which could have regulatory and reputational consequences under European data protection laws such as GDPR.

Organizations should immediately inventory their network to identify the presence of affected Linksys range extender models and firmware versions. Since no official patches are available, the primary mitigation is to isolate these devices from untrusted networks, especially the internet, by placing them behind firewalls or network segmentation controls. Disabling WPS functionality, if configurable, may reduce attack surface. Network administrators should monitor network traffic for unusual activity originating from or targeting these devices. Where possible, replace vulnerable devices with updated hardware from vendors with active security support. Additionally, organizations should implement strict network access controls and consider deploying intrusion detection/prevention systems tuned to detect exploitation attempts targeting this vulnerability. Regular backups and incident response plans should be updated to prepare for potential compromise scenarios. Finally, organizations should maintain close monitoring of vendor communications for any future patches or advisories.