CVE-2025-8831 is a high-severity stack-based buffer overflow vulnerability affecting multiple Linksys Wi-Fi range extender models, including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000, specifically in firmware versions up to 20250801. The vulnerability resides in the remoteManagement function within the /goform/remoteManagement endpoint. An attacker can manipulate the portNumber argument in a crafted request to trigger a stack-based buffer overflow. This overflow can potentially allow remote code execution or cause denial of service conditions. The vulnerability is remotely exploitable without requiring user interaction or prior authentication, increasing its risk profile. The vendor was notified early but has not responded or provided a patch, and a public exploit has been disclosed, though no widespread exploitation has been observed yet. The CVSS v4.0 score is 8.7, reflecting the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no privileges or user interaction required. This vulnerability poses a significant risk to networks using affected Linksys range extenders, as attackers could gain control over the device or disrupt network connectivity remotely.

For European organizations, this vulnerability could lead to severe network disruptions and potential compromise of internal network segments. Linksys range extenders are commonly used in small to medium-sized enterprises and home office environments to extend Wi-Fi coverage. Exploitation could allow attackers to execute arbitrary code on the device, potentially pivoting into corporate networks, intercepting or manipulating traffic, or causing denial of service by crashing the device. Given the remote and unauthenticated nature of the exploit, attackers could target vulnerable devices en masse, leading to widespread outages or espionage risks. Critical infrastructure or organizations relying on these devices for remote management could face operational interruptions. The lack of vendor response and patch availability increases the window of exposure, necessitating immediate mitigation efforts to protect European networks.

Organizations should immediately identify and inventory all Linksys range extenders in use, focusing on the affected models and firmware versions. Since no official patch is currently available, the following steps are recommended: 1) Disable remote management features on these devices to prevent external exploitation; 2) Restrict network access to the management interface by implementing firewall rules or network segmentation, allowing only trusted internal IP addresses; 3) Monitor network traffic for unusual requests targeting /goform/remoteManagement endpoints; 4) Consider replacing vulnerable devices with updated hardware or alternative solutions from vendors with active security support; 5) Regularly check for vendor updates or security advisories for patches; 6) Educate IT staff on recognizing exploitation attempts and maintaining device firmware hygiene. These targeted actions go beyond generic advice by focusing on access control and network-level protections specific to the vulnerability's attack vector.