CVE-2025-13445 is a stack-based buffer overflow vulnerability identified in the Tenda AC21 router firmware version 16.03.08.16. The vulnerability resides in the /goform/SetIpMacBind endpoint, which is responsible for setting IP and MAC address bindings. Due to improper validation and handling of input arguments, an attacker can craft a specially manipulated request that overflows the stack buffer. This overflow can corrupt adjacent memory, potentially allowing remote code execution or causing a denial of service by crashing the device. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, making it highly dangerous. The CVSS 4.0 score of 8.7 reflects its high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges required. Although no confirmed exploits in the wild have been reported, the availability of exploit code increases the likelihood of attacks. The vulnerability affects only the specified firmware version, and no official patches have been linked yet. Attackers targeting this flaw could gain control over the router, intercept or manipulate network traffic, or disrupt network availability, posing significant risks to organizational security.

For European organizations, exploitation of CVE-2025-13445 could lead to severe consequences including unauthorized remote control of network routers, interception or manipulation of sensitive data, and network outages. Critical infrastructure, enterprises, and service providers relying on Tenda AC21 routers may face operational disruptions and data breaches. The ability to exploit this vulnerability without authentication or user interaction increases the attack surface, particularly for devices with exposed management interfaces or weak network segmentation. Compromise of routers can also serve as a pivot point for lateral movement within corporate networks, amplifying the impact. Additionally, disruption of network availability could affect business continuity and critical services. Given the high CVSS score and remote exploitability, the threat is significant for organizations in sectors such as finance, healthcare, government, and telecommunications across Europe.

1. Immediately inventory all Tenda AC21 devices running firmware version 16.03.08.16 within the network. 2. Restrict access to router management interfaces by implementing network segmentation and firewall rules to limit exposure to trusted IP addresses only. 3. Monitor network traffic for unusual requests targeting /goform/SetIpMacBind or other suspicious activity indicative of exploitation attempts. 4. Disable remote management features if not strictly necessary to reduce attack surface. 5. Apply firmware updates or patches from Tenda as soon as they become available; if no official patch exists, consider temporary device replacement or isolation. 6. Employ intrusion detection/prevention systems (IDS/IPS) with signatures for this vulnerability once available. 7. Conduct regular security assessments and penetration tests focusing on network infrastructure devices. 8. Educate IT staff on the risks and detection methods related to this vulnerability to ensure rapid response.