CVE-2025-11325 identifies a stack-based buffer overflow vulnerability in the Tenda AC18 router firmware version 15.03.05.19(6318). The vulnerability resides in an unknown internal function accessed via the /goform/fast_setting_pppoe_set endpoint, specifically through the manipulation of the Username parameter. This buffer overflow occurs when the input exceeds the allocated buffer size on the stack, leading to memory corruption. Because the endpoint is remotely accessible and does not require authentication or user interaction, an attacker can exploit this flaw over the network to execute arbitrary code with elevated privileges on the device. The CVSS 4.0 base score of 8.7 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no required privileges or user interaction. While no confirmed exploits in the wild have been reported, a public proof-of-concept exploit exists, increasing the likelihood of exploitation. The vulnerability could allow attackers to take full control of affected routers, intercept or manipulate network traffic, disrupt network availability, or use the device as a foothold for further attacks. The lack of an official patch at the time of disclosure necessitates immediate attention from users and administrators of Tenda AC18 devices.

The impact of CVE-2025-11325 is significant for organizations and individuals using Tenda AC18 routers. Successful exploitation can lead to full compromise of the device, enabling attackers to execute arbitrary code with elevated privileges. This can result in interception and manipulation of network traffic, loss of confidentiality of sensitive data, disruption of network services, and potential lateral movement within connected networks. For enterprises and small businesses relying on these routers for internet connectivity, this vulnerability poses risks to operational continuity and data security. Additionally, compromised routers can be enlisted into botnets or used as pivot points for further attacks against internal systems. The widespread use of Tenda devices in various regions amplifies the potential scale of impact. Without timely mitigation, attackers can exploit this vulnerability remotely and without authentication, increasing the threat landscape considerably.

To mitigate CVE-2025-11325, organizations should immediately check for firmware updates from Tenda addressing this vulnerability and apply them as soon as they become available. In the absence of an official patch, network administrators should restrict access to the router’s management interfaces, especially the /goform/fast_setting_pppoe_set endpoint, by implementing firewall rules that limit access to trusted IP addresses only. Disabling remote management features or changing default credentials can reduce exposure. Monitoring network traffic for unusual activity or exploitation attempts targeting this endpoint is recommended. Additionally, segmenting the network to isolate vulnerable devices and employing intrusion detection/prevention systems can help detect and prevent exploitation. Users should also consider replacing affected devices with models from vendors with timely security support if patches are not forthcoming. Regular backups and incident response plans should be updated to prepare for potential compromises.