CVE-2025-53711 is a medium severity buffer overflow vulnerability identified in the TP-Link TL-WR841N V11 router model. The vulnerability arises from improper input validation in the /userRpm/WlanNetworkRpm.htm web interface file. Specifically, the device fails to check the size of input parameters before copying them into a buffer, leading to a classic buffer overflow condition (CWE-120). This flaw can be exploited remotely without user interaction or authentication, allowing an attacker to send specially crafted requests to the affected web service. Successful exploitation results in a denial-of-service (DoS) condition by crashing the web service, disrupting normal router operations. The vulnerability affects only the TL-WR841N V11 version, which is no longer supported by TP-Link, meaning no official patches or updates are available. The CVSS 4.0 base score is 6.9, reflecting the network attack vector, low attack complexity, no privileges or user interaction required, but with a high impact on availability. No known exploits are currently reported in the wild. The vulnerability is rooted in classic buffer overflow issues (CWE-120 and CWE-119), which historically have been leveraged for more severe attacks such as remote code execution, but in this case, the impact is limited to service disruption. The lack of vendor support increases the risk for affected users as no remediation is forthcoming from the manufacturer.

For European organizations, the primary impact of this vulnerability is the potential disruption of network connectivity and availability due to denial-of-service conditions on the affected routers. The TL-WR841N V11 is a widely deployed consumer and small office/home office (SOHO) router model, often used in smaller enterprises and remote sites. A DoS attack could interrupt critical business communications, remote access, and internet connectivity, leading to operational downtime and productivity loss. Although the vulnerability does not currently enable remote code execution or data compromise, the disruption of network infrastructure can indirectly affect confidentiality and integrity by forcing fallback to less secure communication methods or causing delays in security monitoring and incident response. The lack of vendor support means organizations cannot rely on official patches, increasing the risk exposure over time. Additionally, if attackers develop exploits in the future, the impact could escalate. European organizations with distributed or remote workforces relying on these devices are particularly vulnerable to service outages. The threat is more pronounced in sectors where network availability is critical, such as finance, healthcare, and public administration.

Given the absence of official patches, European organizations should take proactive and specific steps to mitigate this vulnerability. First, identify and inventory all TL-WR841N V11 devices within the network environment. Replace unsupported devices with newer, supported models that receive regular security updates. If immediate replacement is not feasible, restrict access to the router's web management interface by implementing network segmentation and firewall rules to limit access only to trusted management stations and networks. Disable remote management features if enabled to reduce the attack surface. Employ intrusion detection/prevention systems (IDS/IPS) to monitor and block suspicious traffic targeting the /userRpm/WlanNetworkRpm.htm endpoint. Regularly monitor router logs for unusual activity or crashes indicative of exploitation attempts. Additionally, implement network redundancy and failover mechanisms to minimize operational impact in case of a DoS event. Educate IT staff about the vulnerability and ensure incident response plans include scenarios involving router service disruptions. Finally, maintain up-to-date network device inventories and security posture assessments to quickly identify and remediate unsupported hardware.