CVE-2025-14656 identifies a buffer overflow vulnerability in the Tenda AC20 router firmware version 16.03.08.12, specifically within the httpd daemon handling the /goform/openSchedWifi endpoint. The flaw arises from improper bounds checking when processing the schedStartTime and schedEndTime parameters, allowing an attacker to overflow a buffer. This memory corruption can lead to arbitrary code execution with elevated privileges on the device. The vulnerability is remotely exploitable without requiring authentication or user interaction, making it highly accessible to attackers. The availability of a public exploit increases the likelihood of exploitation despite no current reports of active attacks. Successful exploitation could allow attackers to take full control of the router, manipulate network traffic, intercept sensitive data, or launch further attacks within the network. The vulnerability does not require physical access or user involvement, increasing its threat level. The CVSS v4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no privileges or user interaction needed. The lack of an official patch at the time of publication necessitates immediate risk mitigation strategies to protect affected devices.

For European organizations, exploitation of this vulnerability could lead to severe consequences including unauthorized access to internal networks, interception or manipulation of sensitive communications, and disruption of network availability. Organizations relying on Tenda AC20 routers for critical infrastructure or business operations may face operational downtime, data breaches, or lateral movement by attackers within their networks. The remote and unauthenticated nature of the exploit increases the risk of widespread attacks, especially in environments where these routers are exposed to the internet or untrusted networks. Compromise of these devices could also serve as a foothold for attackers to launch further attacks against connected systems, potentially impacting data privacy and regulatory compliance under GDPR. The public availability of exploit code further elevates the risk of opportunistic attacks targeting European entities using this hardware.

1. Immediately restrict remote access to the router’s management interface by disabling WAN-side access or implementing strict firewall rules to limit access to trusted IP addresses only. 2. Monitor network traffic for unusual activity targeting the /goform/openSchedWifi endpoint or abnormal patterns indicative of exploitation attempts. 3. Apply vendor-provided firmware updates or patches as soon as they become available to remediate the vulnerability. 4. If patches are not yet available, consider temporarily replacing affected devices with alternative hardware or isolating them from critical network segments. 5. Conduct regular vulnerability assessments and penetration testing focused on network infrastructure devices to detect similar weaknesses. 6. Educate IT staff about this vulnerability and ensure incident response plans include steps to address potential exploitation. 7. Employ network segmentation to limit the impact of compromised devices and restrict lateral movement within the network.