CVE-2025-14655 identifies a stack-based buffer overflow vulnerability in the Tenda AC20 router firmware version 16.03.08.12. The vulnerability resides in the formSetRebootTimer function, specifically in the /goform/SetSysAutoRebbotCfg HTTP endpoint handled by the embedded httpd server. By sending a specially crafted HTTP request with a manipulated rebootTime parameter, an attacker can overflow a stack buffer. This overflow can overwrite control data on the stack, potentially allowing remote code execution or causing the device to crash (denial of service). The vulnerability is remotely exploitable without authentication or user interaction, making it highly dangerous. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:L), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no active exploitation in the wild has been reported, the availability of a public exploit increases the likelihood of attacks. The lack of an official patch at the time of disclosure necessitates immediate mitigation strategies. The vulnerability affects a widely deployed consumer and small business router model, which may be used in European homes and enterprises, exposing them to potential compromise or network disruption.

The impact of CVE-2025-14655 on European organizations can be significant. Exploitation can lead to full compromise of affected Tenda AC20 routers, allowing attackers to execute arbitrary code with system-level privileges. This can result in interception or manipulation of network traffic, unauthorized access to internal networks, and disruption of internet connectivity through denial of service. For enterprises relying on these routers for perimeter or branch office connectivity, this could lead to data breaches, lateral movement within networks, and operational downtime. The high severity and remote exploitability without authentication increase the risk profile. Additionally, the public availability of exploit code may accelerate targeted attacks against vulnerable devices in Europe. Organizations in sectors with stringent data protection requirements (e.g., finance, healthcare) face elevated risks of regulatory non-compliance and reputational damage if exploited. The widespread use of Tenda AC20 in residential and small business environments also raises concerns about the security of home office networks, which may serve as entry points for attackers targeting corporate resources.

To mitigate CVE-2025-14655, organizations should first verify if they use Tenda AC20 routers running firmware version 16.03.08.12. Since no official patch is currently available, immediate steps include restricting access to the router’s management interface by implementing network segmentation and firewall rules that block inbound HTTP requests to the /goform/SetSysAutoRebbotCfg endpoint from untrusted networks. Disabling remote management features or changing default management ports can reduce exposure. Monitoring network traffic for anomalous HTTP requests targeting the vulnerable endpoint may help detect exploitation attempts. Organizations should engage with Tenda support channels to obtain firmware updates or security advisories and apply patches promptly once released. Additionally, consider replacing vulnerable devices with models from vendors with stronger security track records if timely patching is not feasible. Educating users about the risks and enforcing strong network access controls will further reduce the attack surface. Regular vulnerability scanning and penetration testing can help identify residual risks related to this vulnerability.