CVE-2025-8826 is a high-severity stack-based buffer overflow vulnerability affecting multiple Linksys range extender models, including RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000, specifically firmware versions up to 20250801. The vulnerability resides in the function um_rp_autochannel within the /goform/RP_setBasicAuto endpoint. It is triggered by manipulating the parameters apcli_AuthMode_2G or apcli_AuthMode_5G, which leads to a stack-based buffer overflow condition. This type of vulnerability can allow an attacker to overwrite critical memory regions on the device, potentially enabling arbitrary code execution or causing a denial of service. The attack can be initiated remotely without user interaction or prior authentication, making it particularly dangerous. The vendor, Linksys, was notified early but has not responded or issued a patch, and the exploit details have been publicly disclosed, increasing the risk of exploitation. The CVSS v4.0 score is 8.7, reflecting the vulnerability's ease of exploitation (network vector, no authentication, no user interaction) and its high impact on confidentiality, integrity, and availability. No known exploits are currently observed in the wild, but public disclosure raises the likelihood of imminent attacks. The lack of vendor response and patch availability further exacerbates the threat landscape for affected devices.

For European organizations, this vulnerability poses a significant risk, especially for enterprises and service providers relying on Linksys range extenders to enhance wireless network coverage. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to compromise network infrastructure, intercept or manipulate sensitive data, or disrupt network availability. This could result in data breaches, loss of business continuity, and reputational damage. Given the remote and unauthenticated nature of the exploit, attackers could target devices en masse, potentially creating botnets or pivoting into internal networks. Organizations with less mature network segmentation or those using these devices in critical environments are particularly vulnerable. Additionally, the absence of a vendor patch means that mitigation relies heavily on network-level controls and device replacement, which may be challenging for large-scale deployments. The impact extends beyond confidentiality and integrity to availability, as exploited devices may crash or become unresponsive, disrupting wireless connectivity.

1. Immediate network segmentation: Isolate affected Linksys range extenders from critical network segments to limit potential lateral movement. 2. Disable remote management interfaces on the affected devices to reduce the attack surface. 3. Monitor network traffic for unusual activity targeting the /goform/RP_setBasicAuto endpoint or abnormal authentication mode parameter usage. 4. Where possible, replace vulnerable devices with models from vendors that have issued patches or are not affected by this vulnerability. 5. Implement strict firewall rules to restrict inbound traffic to the management interfaces of these devices, allowing only trusted IP addresses. 6. Employ intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect exploitation attempts. 7. Maintain an inventory of all affected devices and track firmware versions to prioritize remediation. 8. Engage with Linksys support channels regularly for updates or potential patches. 9. Educate network administrators about this vulnerability and the importance of rapid response to public disclosures. 10. Consider deploying network access control (NAC) solutions to enforce device compliance and prevent vulnerable devices from connecting to sensitive networks.