CVE-2025-14654 is a stack-based buffer overflow vulnerability discovered in the Tenda AC20 router firmware version 16.03.08.12. The vulnerability resides in the formSetPPTPUserList function, which processes input from the /goform/setPptpUserList HTTP endpoint handled by the embedded httpd server. This function improperly handles input arguments, allowing an attacker to overflow a stack buffer by sending a specially crafted HTTP request. The overflow can corrupt the stack, enabling remote code execution or denial of service on the device. The vulnerability requires no authentication or user interaction, making it remotely exploitable over the network. The exploit code is publicly available, increasing the likelihood of attacks. The CVSS v4.0 score of 8.7 indicates a high severity due to network attack vector, low attack complexity, no privileges required, and high impact on confidentiality, integrity, and availability. The vulnerability affects only firmware version 16.03.08.12 of the Tenda AC20 router, a consumer and small business networking device. No official patch links are currently provided, highlighting the urgency for mitigations. The flaw could be leveraged to gain control over the router, intercept or manipulate network traffic, or disrupt network availability.

For European organizations, exploitation of CVE-2025-14654 could lead to severe consequences including unauthorized remote control of affected routers, interception and manipulation of sensitive network traffic, and disruption of internet connectivity. This could compromise confidentiality by exposing internal communications, integrity by altering data flows, and availability by causing router crashes or persistent denial of service. Small and medium enterprises using Tenda AC20 devices as their primary network gateway are particularly vulnerable. Critical infrastructure sectors relying on these routers for VPN or remote access functions could face operational disruptions. The public availability of exploit code increases the risk of opportunistic attacks and automated scanning. Additionally, compromised routers could be recruited into botnets, amplifying broader cyber threats. The lack of patches exacerbates the risk, potentially leading to prolonged exposure. Organizations may also face compliance and reputational risks if breaches occur due to unmitigated vulnerabilities in network devices.

Immediate mitigation steps include: 1) Identifying and inventorying all Tenda AC20 routers running firmware version 16.03.08.12 within the network. 2) Applying any available firmware updates from Tenda as soon as they are released; if no official patch is available, contact the vendor for guidance. 3) Implementing network-level protections such as firewall rules or intrusion prevention systems to block or monitor HTTP requests targeting the /goform/setPptpUserList endpoint. 4) Restricting remote management access to trusted IP addresses and disabling unnecessary services on the router. 5) Employing network segmentation to isolate vulnerable devices from critical assets. 6) Monitoring network traffic for anomalous patterns indicative of exploitation attempts. 7) Educating IT staff about the vulnerability and ensuring incident response plans include steps for compromised routers. 8) Considering temporary replacement of vulnerable devices with alternative hardware if patching is delayed. These measures go beyond generic advice by focusing on specific endpoint identification, network controls, and operational readiness.