CVE-2025-6751 is a critical buffer overflow vulnerability found in the Linksys E8450 router, specifically affecting firmware version 1.2.00.360516 and earlier. The flaw exists in the HTTP POST request handler component, within the function set_device_language in the portal.cgi file. An attacker can exploit this vulnerability by manipulating the 'dut_language' argument sent in an HTTP POST request. This manipulation causes a buffer overflow, which can lead to arbitrary code execution or denial of service on the affected device. The vulnerability is remotely exploitable without requiring user interaction or authentication, making it highly dangerous. The vendor, Linksys, was notified early but has not responded or issued a patch, increasing the risk of exploitation. Although no known exploits have been observed in the wild yet, the public disclosure of the exploit code raises the likelihood of imminent attacks. The CVSS 4.0 score of 8.7 (high severity) reflects the ease of exploitation (network attack vector, low attack complexity, no privileges or user interaction required) and the significant impact on confidentiality, integrity, and availability of the device. Given that routers like the Linksys E8450 are critical network infrastructure components, successful exploitation could allow attackers to intercept, modify, or disrupt network traffic, potentially compromising connected devices and sensitive data within the network.

For European organizations, this vulnerability poses a significant risk to network security and operational continuity. The Linksys E8450 is a consumer and small business router, so organizations using this device in branch offices or home office setups could be targeted. Exploitation could lead to unauthorized network access, interception of confidential communications, and disruption of internet connectivity. This could affect data confidentiality, integrity, and availability, potentially leading to data breaches, loss of trust, and operational downtime. In sectors with strict data protection regulations such as GDPR, exploitation could result in compliance violations and financial penalties. Additionally, compromised routers could be leveraged as entry points for lateral movement within corporate networks or as part of botnets for broader attacks. The lack of an official patch from the vendor exacerbates the risk, forcing organizations to rely on mitigations or device replacement.

Given the absence of an official patch, European organizations should take immediate and specific actions: 1) Identify and inventory all Linksys E8450 devices running vulnerable firmware versions within their networks. 2) Where possible, isolate these devices from direct internet exposure by placing them behind additional firewalls or network segmentation to limit attack surface. 3) Disable remote management features on the affected routers to prevent external exploitation. 4) Implement strict network monitoring and intrusion detection rules to detect anomalous HTTP POST requests targeting the portal.cgi endpoint or unusual traffic patterns indicative of exploitation attempts. 5) Consider replacing vulnerable devices with updated hardware or routers from vendors with active security support. 6) For critical environments, deploy network-level protections such as Web Application Firewalls (WAFs) or proxy solutions that can filter malicious HTTP requests. 7) Educate IT staff about this vulnerability and ensure rapid incident response capabilities are in place. 8) Regularly review and update network device firmware and maintain communication with vendors for security advisories.