CVE-2025-11387 identifies a stack-based buffer overflow vulnerability in the Tenda AC15 router firmware version 15.03.05.18. The flaw resides in an unspecified function handling the /goform/fast_setting_pppoe_set endpoint, specifically when processing the Password parameter. By sending a specially crafted request with a manipulated Password argument, an attacker can overflow the stack buffer, potentially overwriting return addresses or control data. This can lead to arbitrary code execution or denial of service on the device. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges needed. Although no known exploits are currently active in the wild, the public disclosure of exploit details raises the likelihood of imminent attacks. The affected product, Tenda AC15, is a widely used consumer and small office router, often deployed in environments with limited security controls. The lack of available patches at the time of disclosure necessitates immediate mitigation steps to reduce exposure. This vulnerability could be leveraged by attackers to gain persistent control over network infrastructure, intercept or manipulate traffic, or disrupt network services.

For European organizations, exploitation of CVE-2025-11387 could result in severe consequences including unauthorized access to internal networks, interception of sensitive data, and disruption of critical network services. Compromise of Tenda AC15 routers could serve as a foothold for lateral movement within corporate or governmental networks, increasing the risk of data breaches or espionage. Small and medium enterprises, as well as home office setups relying on these routers, may face significant operational impact due to device instability or takeover. The vulnerability threatens confidentiality by enabling attackers to access network traffic, integrity by allowing modification of router configurations or injected malicious payloads, and availability by causing device crashes or persistent denial of service. Given the remote and unauthenticated nature of the exploit, attackers can target exposed devices over the internet, amplifying the risk to organizations with poorly secured network perimeters. The absence of a patch at disclosure time further elevates the threat, necessitating urgent defensive measures to prevent exploitation.

1. Immediately restrict remote access to the Tenda AC15 router management interfaces by disabling WAN-side administration or applying strict firewall rules to limit access to trusted IP addresses only. 2. Implement network segmentation to isolate routers from critical internal systems, reducing the potential impact of compromise. 3. Monitor network traffic for unusual requests targeting /goform/fast_setting_pppoe_set or anomalous POST requests containing suspicious Password parameters. 4. Apply vendor firmware updates as soon as they become available to address the vulnerability directly. 5. If patching is not immediately possible, consider temporary replacement of affected devices with routers from vendors with timely security support. 6. Educate network administrators on the risks of exposed router management interfaces and enforce strong password policies to reduce attack surface. 7. Employ intrusion detection/prevention systems capable of detecting buffer overflow attempts or malformed HTTP requests targeting router endpoints. 8. Regularly audit network devices for firmware versions and configuration compliance to ensure vulnerabilities are promptly addressed.