CVE-2025-11528 is a stack-based buffer overflow vulnerability identified in the Tenda AC7 router firmware version 15.03.06.44. The flaw exists in an unspecified function within the /goform/saveAutoQos endpoint, where manipulation of the 'enable' argument leads to a buffer overflow on the stack. This vulnerability allows remote attackers to execute arbitrary code on the device without requiring authentication or user interaction, as indicated by the CVSS 4.0 vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability impacts confidentiality, integrity, and availability with high severity, as exploitation can lead to full device compromise, enabling attackers to intercept, modify, or disrupt network traffic. The vulnerability is remotely exploitable over the network, making it a significant threat to any organization using affected Tenda AC7 devices. Although no known exploits are currently observed in the wild, a public exploit is available, increasing the likelihood of future attacks. The lack of a patch link suggests that a firmware update may not yet be released, emphasizing the need for proactive mitigation. The vulnerability's presence in a consumer-grade router used in enterprise and home environments alike broadens the attack surface. Attackers could leverage this flaw to establish persistent access, pivot within networks, or launch further attacks against connected systems.

For European organizations, the impact of CVE-2025-11528 can be substantial. Compromise of Tenda AC7 routers could lead to interception and manipulation of sensitive data traversing the network, undermining confidentiality. Integrity of network traffic and device configurations can be altered, potentially disrupting business operations or enabling further lateral movement by attackers. Availability may be affected if the device is rendered inoperable or used as a launchpad for denial-of-service attacks. Organizations relying on Tenda AC7 devices for critical network functions, including SMEs and some public sector entities, face increased risk. The remote, unauthenticated nature of the exploit lowers the barrier for attackers, including cybercriminals and state-sponsored actors. The availability of a public exploit increases the likelihood of opportunistic attacks targeting vulnerable devices. This vulnerability could also be exploited to infiltrate networks of European critical infrastructure if these routers are deployed there, amplifying potential national security concerns.

Immediate mitigation should focus on network-level controls to limit exposure of the vulnerable /goform/saveAutoQos endpoint. Organizations should implement strict firewall rules to block inbound traffic to the router's management interfaces from untrusted networks. Network segmentation can isolate vulnerable devices from sensitive systems. Monitoring network traffic for unusual requests to the /goform/saveAutoQos path can help detect exploitation attempts. Until an official firmware patch is released, consider disabling AutoQoS features if possible or replacing affected devices with alternatives not impacted by this vulnerability. Employ intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect attempts to exploit this buffer overflow. Regularly check vendor communications for firmware updates and apply patches promptly once available. Educate network administrators about the vulnerability and signs of compromise. For organizations with large deployments, conduct an inventory to identify all affected devices and prioritize remediation efforts accordingly.