CVE-2025-51089 is a heap-based buffer overflow vulnerability identified in the Tenda AC8V4 router firmware version V16.03.34.06. The vulnerability arises from improper handling of the 'mac' argument in the /goform/GetParentControlInfo endpoint. Specifically, when the 'mac' parameter is manipulated with crafted input, it triggers a heap overflow condition. Heap overflows occur when data is written beyond the allocated heap buffer boundaries, potentially allowing an attacker to overwrite adjacent memory, corrupt data structures, or execute arbitrary code. This vulnerability is particularly concerning because it targets a network device firmware component that is often exposed to local network users or potentially remote attackers if the management interface is accessible externally. The lack of a CVSS score and absence of known exploits in the wild suggests this vulnerability is newly disclosed and not yet weaponized, but the technical nature of heap overflows typically allows for exploitation leading to remote code execution or denial of service. The vulnerability does not specify affected versions beyond the noted firmware version, and no patches or mitigations have been published at this time. The endpoint involved, /goform/GetParentControlInfo, is likely part of the parental control feature set, which may be accessible via the router's web management interface. Exploitation would require sending a specially crafted request with a malicious 'mac' parameter to trigger the overflow.

For European organizations, the impact of this vulnerability can be significant, especially for enterprises, ISPs, or small businesses using Tenda AC8V4 routers as part of their network infrastructure. Successful exploitation could allow attackers to execute arbitrary code on the router, leading to full compromise of the device. This could result in interception or manipulation of network traffic, disruption of internet connectivity (denial of service), or pivoting attacks into the internal network. Given that routers are critical network infrastructure components, their compromise can undermine confidentiality, integrity, and availability of organizational data and services. Additionally, compromised routers can be used as launch points for broader attacks such as botnets or lateral movement. The parental control feature targeted by this vulnerability may be enabled in environments with sensitive user data or regulatory requirements, increasing the risk profile. The absence of known exploits currently reduces immediate risk, but the potential for future weaponization necessitates proactive mitigation.

1. Immediate mitigation should include restricting access to the router's management interface, ensuring it is not exposed to untrusted networks or the internet. 2. Network segmentation should be applied to isolate management interfaces from general user networks. 3. Monitor network traffic for unusual requests targeting /goform/GetParentControlInfo or abnormal 'mac' parameter values. 4. Disable parental control features if not required, reducing the attack surface. 5. Engage with Tenda support or vendor channels to obtain firmware updates or patches addressing this vulnerability as soon as they become available. 6. Implement strict input validation and filtering at network perimeters to detect and block malformed requests. 7. Conduct regular security audits and vulnerability scans on network devices to identify outdated firmware versions. 8. Prepare incident response plans to quickly isolate and remediate compromised devices.