CVE-2025-11527 identifies a stack-based buffer overflow vulnerability in the Tenda AC7 router firmware version 15.03.06.44. The vulnerability resides in an unspecified function associated with the /goform/fast_setting_pppoe_set endpoint, which processes the Password parameter. By sending a specially crafted request manipulating this Password argument, an attacker can overflow the stack buffer, potentially overwriting the return address or other control data on the stack. This can lead to arbitrary code execution with elevated privileges on the device. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS 4.0 base score is 8.7 (high), reflecting the network attack vector, low complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no known exploits are currently observed in the wild, the public disclosure of exploit code increases the likelihood of exploitation attempts. The affected product, Tenda AC7, is a consumer and small office router commonly used in various regions, including Europe. The lack of an official patch at the time of disclosure necessitates immediate mitigation efforts to reduce exposure. Attackers exploiting this vulnerability could gain full control over the router, enabling interception or manipulation of network traffic, disruption of services, or pivoting to internal networks.

For European organizations, exploitation of CVE-2025-11527 could lead to severe consequences. Compromise of Tenda AC7 routers may allow attackers to execute arbitrary code, resulting in full device takeover. This jeopardizes the confidentiality and integrity of network traffic passing through the router, potentially exposing sensitive data or enabling man-in-the-middle attacks. Availability could also be impacted if attackers disrupt router functionality, causing network outages. Organizations relying on these routers for critical connectivity or remote access could face operational disruptions. Furthermore, compromised routers can serve as footholds for lateral movement into internal networks, increasing the risk of broader intrusions. The remote, unauthenticated nature of the exploit means attackers can launch attacks from anywhere, increasing the threat landscape. European enterprises with remote or distributed offices using Tenda AC7 devices are particularly vulnerable. The public disclosure of exploit code raises the risk of widespread scanning and exploitation attempts, necessitating urgent defensive measures.

1. Immediately monitor Tenda’s official channels for firmware updates addressing CVE-2025-11527 and apply patches as soon as they become available. 2. Until patches are released, restrict access to the router’s management interfaces by disabling remote administration or limiting access via firewall rules to trusted IP addresses only. 3. Segment networks to isolate Tenda AC7 devices from critical infrastructure and sensitive data environments, reducing the impact of potential compromise. 4. Employ network intrusion detection/prevention systems (IDS/IPS) to detect anomalous traffic patterns or exploit attempts targeting /goform/fast_setting_pppoe_set or suspicious POST requests. 5. Conduct regular audits of router configurations to ensure strong, unique passwords and disable unnecessary services or features that increase attack surface. 6. Educate IT staff and users about the risks associated with this vulnerability and encourage vigilance for unusual network behavior. 7. Consider replacing vulnerable Tenda AC7 devices with routers from vendors with stronger security track records if patching is delayed or unsupported. 8. Implement network-level monitoring to detect potential lateral movement from compromised routers into internal systems.