CVE-2025-7423 is a critical stack-based buffer overflow vulnerability identified in the Tenda O3V2 wireless device, specifically version 1.0.0.12(3880). The flaw exists in the function formWifiMacFilterSet within the HTTP daemon component, located at /goform/setWrlFilterList. This function processes the macList argument, which is improperly handled, allowing an attacker to overflow the stack buffer. Because the vulnerability is remotely exploitable without authentication or user interaction, an attacker can send a specially crafted HTTP request to the device to trigger the overflow. This can lead to arbitrary code execution, potentially allowing full control over the device. The vulnerability has a CVSS 4.0 base score of 8.7, reflecting high severity due to its network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. Although no public exploits are currently observed in the wild, the exploit code has been disclosed publicly, increasing the risk of exploitation. The vulnerability affects a specific firmware version of the Tenda O3V2, a device commonly used for wireless connectivity in small office and home environments. The stack-based buffer overflow can be leveraged to execute malicious payloads, disrupt network services, or pivot into internal networks, posing significant security risks.

For European organizations, this vulnerability poses a substantial risk, especially for small and medium enterprises (SMEs) and residential users relying on Tenda O3V2 devices for wireless connectivity. Successful exploitation can lead to device compromise, enabling attackers to intercept or manipulate network traffic, disrupt internet access, or use the device as a foothold for further attacks within corporate or home networks. This could result in data breaches, loss of confidentiality, and operational downtime. Given the remote and unauthenticated nature of the exploit, attackers can target vulnerable devices en masse, potentially leading to widespread network disruptions. Critical infrastructure or organizations with remote sites using these devices may face increased exposure. Additionally, compromised devices could be conscripted into botnets, amplifying the threat landscape in Europe. The lack of a patch at the time of disclosure further exacerbates the risk, necessitating immediate mitigation efforts to protect sensitive data and maintain network integrity.

1. Immediate network segmentation: Isolate Tenda O3V2 devices from critical network segments to limit potential lateral movement if compromised. 2. Disable remote management interfaces or restrict access to trusted IP addresses only, reducing exposure to remote exploitation. 3. Monitor network traffic for unusual HTTP requests targeting /goform/setWrlFilterList or abnormal macList parameter usage indicative of exploitation attempts. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or anomaly detection tuned to detect buffer overflow attempts against Tenda devices. 5. Regularly audit and inventory network devices to identify all Tenda O3V2 units and verify firmware versions. 6. Engage with Tenda support channels to obtain firmware updates or patches as soon as they become available. 7. If patching is not immediately possible, consider replacing vulnerable devices with alternative hardware from vendors with timely security support. 8. Educate network administrators about this vulnerability to ensure rapid response and incident handling if exploitation is suspected.