CVE-2025-57078 is a stack overflow vulnerability identified in the Tenda G3 router firmware version 3.0br_V15.11.0.17. The flaw exists in the handling of the pppoeServerWhiteMacIndex parameter within the formModifyPppAuthWhiteMac function. Specifically, this parameter is not properly validated or sanitized, allowing an attacker to craft a malicious request that triggers a stack overflow condition. This vulnerability can be exploited remotely by sending a specially crafted request to the affected device, causing it to crash or become unresponsive, resulting in a Denial of Service (DoS). The vulnerability does not require authentication or user interaction, increasing its potential for exploitation. Although no known exploits are currently reported in the wild, the nature of the vulnerability and the widespread use of Tenda routers in consumer and small business environments make it a significant concern. The lack of a CVSS score indicates that the vulnerability is newly disclosed and has not yet undergone formal severity assessment. The stack overflow could potentially be leveraged for further attacks, such as remote code execution, but currently, only DoS impact is confirmed.

For European organizations, the primary impact of CVE-2025-57078 is service disruption due to Denial of Service on network infrastructure devices using the affected Tenda G3 firmware. This can lead to loss of internet connectivity, interruption of business operations, and potential cascading effects on dependent services. Small and medium enterprises (SMEs) and home offices that rely on Tenda routers for their network connectivity are particularly vulnerable. The disruption could affect remote work capabilities, VoIP communications, and access to cloud services. Additionally, the downtime could expose organizations to secondary risks such as delayed incident response or inability to access security monitoring tools. While the vulnerability currently only enables DoS, the stack overflow nature suggests a risk of escalation if further exploitation techniques are developed. The absence of known exploits provides a window for mitigation before active attacks emerge.

Organizations should immediately identify and inventory all Tenda G3 routers running firmware version 3.0br_V15.11.0.17. Since no official patch links are currently available, it is critical to monitor Tenda's official channels for firmware updates addressing this vulnerability. In the interim, network administrators should implement network-level protections such as firewall rules to restrict access to router management interfaces from untrusted networks, especially blocking unsolicited inbound traffic targeting the PPPoE server functionality. Deploying intrusion detection/prevention systems (IDS/IPS) with custom signatures to detect anomalous requests to the pppoeServerWhiteMacIndex parameter can help mitigate exploitation attempts. Organizations should also consider segmenting network devices to limit exposure and enforce strict access controls. Regular backups of router configurations and readiness to perform device reboots can reduce downtime impact. Finally, educating IT staff about the vulnerability and monitoring security advisories will ensure timely response to emerging threats or patches.