CVE-2025-9014 identifies a vulnerability in the TP-Link TL-WR841N v14 router, specifically in the web portal's handling of the HTTP referer header. The root cause is improper input validation, classified under CWE-20, which leads to a Null Pointer Dereference condition. When the web portal processes a crafted referer header, it dereferences a null pointer, causing the web service to crash and resulting in a denial of service (DoS). This vulnerability can be exploited remotely without authentication or user interaction, making it accessible to any attacker capable of sending HTTP requests to the router's management interface. The affected firmware versions are those prior to build 250908. The CVSS 4.0 base score is 6.3, reflecting a medium severity level, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and low impact on availability (VA:L). There is no impact on confidentiality or integrity. No known exploits have been reported in the wild yet. The vulnerability primarily threatens the availability of the router's management interface, potentially disrupting network administration and causing temporary loss of control over the device. The lack of authentication requirement increases the risk, especially if the router's web interface is exposed to untrusted networks. However, the impact is limited to the web portal service and does not directly compromise the router's core functionality or data confidentiality. The vulnerability highlights the importance of robust input validation in embedded device web interfaces and the risks posed by exposing management portals to external networks.

For European organizations, this vulnerability could lead to temporary denial of service on the TP-Link TL-WR841N v14 router's web management portal. This disruption can impede network administrators' ability to configure or monitor the device remotely, potentially delaying incident response or routine maintenance. In environments where these routers serve as critical network gateways or are part of larger managed networks, such interruptions could degrade network availability and operational continuity. Although the vulnerability does not allow direct data compromise or persistent device control, the loss of management access can increase exposure to other threats if the device cannot be promptly secured or updated. Small and medium enterprises, home offices, and public institutions using this router model without adequate network segmentation or access controls are particularly at risk. The absence of known exploits reduces immediate threat levels, but the ease of exploitation and unauthenticated access mean attackers could leverage this flaw in targeted denial-of-service campaigns. Additionally, organizations relying on remote management over WAN interfaces without VPN or firewall protections are more vulnerable. Overall, the impact is primarily on availability and operational stability rather than confidentiality or integrity.

1. Apply firmware updates from TP-Link as soon as they become available to address this vulnerability. Monitor TP-Link's official channels for patch releases related to build 250908 or later. 2. Restrict access to the router's web management interface by limiting it to trusted internal networks only; disable remote management over WAN interfaces unless absolutely necessary. 3. Implement network segmentation to isolate management interfaces from general user traffic and untrusted networks. 4. Use firewall rules to block or filter suspicious HTTP requests containing malformed or unexpected referer headers targeting the router's IP address. 5. Monitor network traffic and router logs for unusual patterns or repeated requests to the web portal that could indicate exploitation attempts. 6. Consider deploying intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts of this vulnerability. 7. Educate network administrators about the risks of exposing router management interfaces and enforce strong access control policies. 8. If firmware updates are delayed, consider temporarily disabling the web management interface and use alternative management methods such as console access or secure protocols.