CVE-2026-3378 identifies a buffer overflow vulnerability in the Tenda F453 router firmware version 1.0.0.3, specifically within the fromqossetting function of the /goform/qossetting endpoint. The vulnerability arises from improper validation or sanitization of the qos parameter, allowing an attacker to send a specially crafted request that overflows a buffer in memory. This overflow can corrupt adjacent memory, potentially enabling arbitrary code execution or causing the device to crash, resulting in denial of service. The flaw is remotely exploitable without requiring authentication or user interaction, significantly increasing its risk profile. The CVSS v4.0 score of 8.7 reflects its high severity, with metrics indicating network attack vector, low attack complexity, no privileges required, no user interaction, and high impact on confidentiality, integrity, and availability. While no confirmed exploits in the wild have been reported yet, a public exploit exists, making it easier for threat actors to weaponize this vulnerability. The lack of an official patch at the time of disclosure necessitates immediate defensive measures. This vulnerability affects only firmware version 1.0.0.3 of the Tenda F453 router, a device commonly used in small to medium-sized enterprise and home networks. Exploitation could allow attackers to gain unauthorized control over the router, intercept or manipulate network traffic, and disrupt network services.

The impact of CVE-2026-3378 is significant for organizations using the Tenda F453 router, as exploitation can lead to complete compromise of the device. Attackers could execute arbitrary code remotely, potentially gaining persistent control over the router and the internal network. This compromises confidentiality by enabling interception or manipulation of sensitive data passing through the device. Integrity is affected as attackers can alter router configurations or network traffic. Availability is at risk due to potential denial of service from crashes or intentional disruptions. For enterprises, this could lead to network outages, data breaches, and lateral movement into internal systems. Home users may experience loss of internet connectivity and exposure of private information. The remote, unauthenticated nature of the exploit increases the likelihood of widespread attacks, especially once automated exploit tools become available. The absence of a patch at disclosure time further exacerbates the risk, making timely mitigation critical to prevent exploitation.

1. Immediately isolate affected Tenda F453 devices from untrusted networks, especially the internet, to reduce exposure. 2. Disable remote management interfaces and services on the router to prevent external exploitation. 3. Implement strict network segmentation to limit access to the router from only trusted internal hosts. 4. Monitor network traffic and router logs for unusual or malformed requests targeting /goform/qossetting or abnormal behavior indicative of exploitation attempts. 5. Apply any firmware updates or patches released by Tenda as soon as they become available. 6. If no patch is available, consider replacing affected devices with alternative hardware not vulnerable to this issue. 7. Employ intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability or exploit patterns. 8. Educate network administrators about the vulnerability and ensure incident response plans include steps for this threat. 9. Regularly audit router configurations and firmware versions to ensure compliance with security best practices. 10. Limit administrative access to the router to trusted personnel and use strong authentication methods where possible.