CVE-2025-11525 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 handling the /goform/SetUpnpCfg endpoint, specifically through manipulation of the upnpEn argument. This parameter is improperly validated, allowing an attacker to overflow a stack buffer remotely without requiring authentication or user interaction. The vulnerability is exploitable over the network (AV:N) with low attack complexity (AC:L) and no privileges required (PR:L indicates limited privileges, but the CVSS vector states AT:N meaning no authentication is needed). Successful exploitation can lead to arbitrary code execution with high impact on confidentiality, integrity, and availability of the device. The vulnerability has been publicly disclosed, though no known exploits in the wild have been reported yet. The Tenda AC7 is a widely used consumer and small business router, making this vulnerability significant for many users. The lack of available patches at the time of disclosure increases the urgency for mitigation. The vulnerability's CVSS 4.0 score is 8.7 (high), reflecting its critical nature and ease of exploitation. Attackers could leverage this flaw to gain control over the router, intercept or manipulate network traffic, or pivot into internal networks.

The impact of CVE-2025-11525 is substantial for organizations and individuals using Tenda AC7 routers. Exploitation can result in full compromise of the router, allowing attackers to execute arbitrary code with elevated privileges. This can lead to interception and manipulation of network traffic, disruption of internet connectivity, and potential lateral movement into internal networks. Confidential data passing through the router could be exposed or altered, undermining privacy and security. For enterprises relying on these devices for network access or segmentation, the vulnerability poses a risk of broader network compromise. The remote and unauthenticated nature of the exploit increases the attack surface, enabling attackers to target vulnerable devices from anywhere on the internet. The absence of known patches at disclosure time means many devices remain exposed, increasing the likelihood of exploitation attempts. The vulnerability could also be leveraged in botnet campaigns or as a foothold for further attacks against connected systems.

1. Immediately disable UPnP functionality on Tenda AC7 routers if it is not essential, as the vulnerability is triggered via the UPnP configuration endpoint. 2. Restrict remote management access to the router by disabling WAN-side administration or limiting it to trusted IP addresses. 3. Implement network segmentation to isolate vulnerable devices from critical infrastructure and sensitive data. 4. Monitor network traffic for unusual requests to /goform/SetUpnpCfg or anomalous UPnP activity that could indicate exploitation attempts. 5. Apply any available firmware updates from Tenda as soon as they are released addressing this vulnerability. 6. If patches are not yet available, consider replacing affected devices with alternative hardware from vendors with timely security support. 7. Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability once they become available. 8. Educate users and administrators about the risks of exposing router management interfaces to the internet and the importance of secure configurations.