CVE-2025-12213 is a stack-based buffer overflow vulnerability identified in the Tenda O3 device firmware version 1.0.0.10(2478). The vulnerability resides in the handling of the 'lan' parameter within the /goform/setVlanConfig endpoint, specifically in the SetValue and GetValue functions. Improper validation or sanitization of this parameter allows an attacker to overflow the stack buffer remotely, without requiring authentication or user interaction. This can lead to arbitrary code execution, enabling the attacker to take control of the device or cause a denial of service by crashing the system. The vulnerability is remotely exploitable over the network, making it particularly dangerous for exposed devices. The CVSS 4.0 base score is 8.7, reflecting high impact on confidentiality, integrity, and availability, with low attack complexity and no privileges or user interaction required. Although no confirmed exploits in the wild have been reported yet, public disclosure of the exploit code increases the risk of imminent attacks. The affected product, Tenda O3, is commonly used in small office and home office environments, as well as in some enterprise network segments. The lack of an official patch link suggests that vendors and users must monitor for firmware updates or apply interim mitigations. Given the nature of the vulnerability, attackers could leverage it to pivot into internal networks or disrupt critical network services.

For European organizations, this vulnerability poses a significant risk to network infrastructure security, especially for those deploying Tenda O3 devices in their environments. Successful exploitation could lead to unauthorized remote control of network devices, enabling attackers to intercept, modify, or disrupt network traffic. This threatens the confidentiality and integrity of sensitive data and can cause widespread availability issues through device crashes or network outages. Critical sectors such as finance, healthcare, government, and telecommunications that rely on stable and secure network equipment are particularly vulnerable. The remote and unauthenticated nature of the exploit increases the likelihood of attacks, potentially leading to lateral movement within corporate networks. Additionally, the public disclosure of exploit code may accelerate targeted attacks against European entities. The absence of a patch at the time of disclosure means organizations must rely on network-level defenses and monitoring to mitigate risk. The impact extends to supply chain security if Tenda O3 devices are integrated into managed services or third-party infrastructures.

1. Immediately inventory and identify all Tenda O3 devices running firmware version 1.0.0.10(2478) within the network. 2. Restrict network access to the /goform/setVlanConfig endpoint by implementing firewall rules or access control lists (ACLs) to limit exposure to trusted management networks only. 3. Employ network segmentation to isolate vulnerable devices from critical systems and sensitive data environments. 4. Monitor network traffic for anomalous requests targeting the /goform/setVlanConfig endpoint, using intrusion detection/prevention systems (IDS/IPS) with updated signatures or custom rules. 5. Disable remote management interfaces on Tenda O3 devices if not strictly necessary, or enforce strong authentication and VPN access for remote administration. 6. Engage with Tenda or authorized vendors to obtain firmware updates or patches as soon as they become available, and plan for prompt deployment. 7. Consider temporary replacement or removal of vulnerable devices in high-risk environments until a patch is applied. 8. Conduct regular vulnerability assessments and penetration tests focusing on network devices to detect exploitation attempts. 9. Educate IT and security teams about this specific vulnerability and the importance of rapid response to firmware vulnerabilities in network equipment.