CVE-2025-11356 identifies a critical buffer overflow vulnerability in the Tenda AC23 router firmware versions up to 16.03.07.52. The vulnerability resides in the sscanf function handling input parameters on the /goform/SetStaticRouteCfg endpoint, which is accessible remotely. By crafting malicious input to this endpoint, an attacker can overflow the buffer, potentially overwriting memory and executing arbitrary code on the device. The vulnerability requires no user interaction and no prior authentication, making it highly exploitable over the network. The CVSS 4.0 score of 8.7 reflects the high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. The exploitability is enhanced by the public availability of proof-of-concept exploit code, although no confirmed active exploitation has been reported yet. The flaw affects a wide range of firmware versions, indicating a longstanding issue in the product line. The vulnerability could allow attackers to take full control of affected routers, enabling interception or manipulation of network traffic, deployment of persistent malware, or disruption of network services. Given the critical role of routers in network infrastructure, this vulnerability poses a significant threat to both enterprise and consumer environments using Tenda AC23 devices.

The impact of CVE-2025-11356 is severe for organizations relying on Tenda AC23 routers. Successful exploitation can lead to full compromise of the router, allowing attackers to execute arbitrary code with system-level privileges. This can result in interception and manipulation of sensitive network traffic, unauthorized access to internal networks, and potential lateral movement within corporate environments. The integrity of network configurations can be altered, leading to persistent backdoors or denial of service conditions. For enterprises, this could mean exposure of confidential data, disruption of business operations, and damage to reputation. Consumer users may face privacy violations and loss of internet connectivity. The widespread use of Tenda routers in various regions increases the attack surface. The lack of authentication and user interaction requirements further amplifies the risk, making automated mass exploitation plausible once weaponized. The public availability of exploit code accelerates the potential for rapid attacks, especially targeting unpatched devices.

1. Immediate firmware upgrade: Organizations and users should monitor Tenda's official channels for patches addressing this vulnerability and apply updates promptly once released. 2. Network segmentation: Isolate Tenda AC23 routers from critical network segments to limit potential lateral movement if compromised. 3. Access control: Restrict remote management interfaces and block access to the /goform/SetStaticRouteCfg endpoint via firewall rules or network ACLs. 4. Intrusion detection: Deploy network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts targeting this vulnerability. 5. Disable remote administration: If not required, disable remote management features on the router to reduce exposure. 6. Monitor logs and traffic: Continuously monitor router logs and network traffic for unusual activity indicative of exploitation attempts. 7. Vendor engagement: Engage with Tenda support for guidance and potential interim mitigations. 8. Device replacement: Consider replacing vulnerable devices in high-security environments if patches are delayed or unavailable. These steps go beyond generic advice by focusing on immediate containment, network-level controls, and proactive monitoring tailored to this specific vulnerability and device.