CVE-2025-57058 is a security vulnerability identified in the Tenda G3 router firmware version 3.0br_V15.11.0.17. The vulnerability arises from multiple stack overflow conditions within the formSetDebugCfg function, specifically triggered via the pEnable, pLevel, and pModule parameters. Stack overflow vulnerabilities occur when a program writes more data to a buffer located on the stack than it can hold, potentially overwriting adjacent memory. In this case, the crafted input parameters can cause the router's firmware to overwrite critical memory areas, leading to instability or crashes. The primary impact of this vulnerability is a Denial of Service (DoS), where an attacker can send a specially crafted request to the affected device, causing it to become unresponsive or reboot unexpectedly. This vulnerability does not require authentication or user interaction, making it exploitable remotely by an unauthenticated attacker. Although no known exploits are currently reported in the wild, the presence of multiple stack overflows in a network-facing function represents a significant risk. The lack of a CVSS score and absence of patches at the time of publication indicate that this vulnerability is newly disclosed and may not yet have official remediation. Given that Tenda routers are commonly used in home and small office environments, exploitation could disrupt internet connectivity and network availability for affected users.

For European organizations, especially small and medium enterprises (SMEs) and home office users relying on Tenda G3 routers, this vulnerability poses a risk of network disruption through Denial of Service attacks. The DoS condition could interrupt critical business communications, remote work capabilities, and access to cloud services. While the vulnerability does not appear to allow remote code execution or data theft, the loss of availability can have cascading effects on productivity and operational continuity. In sectors such as finance, healthcare, and critical infrastructure where network reliability is paramount, even temporary outages can lead to financial losses and reputational damage. Additionally, if exploited at scale, attackers could leverage this vulnerability to create widespread disruptions or as part of a larger attack campaign targeting network infrastructure. The absence of known exploits currently limits immediate risk, but the ease of exploitation without authentication suggests that threat actors could develop attacks rapidly once details become widely known.

To mitigate this vulnerability, European organizations should first identify any Tenda G3 routers running firmware version 3.0br_V15.11.0.17 within their networks. Immediate steps include isolating these devices from critical network segments and restricting inbound access to management interfaces from untrusted networks. Network administrators should monitor network traffic for unusual or malformed requests targeting the formSetDebugCfg function parameters. Since no official patches are currently available, organizations should contact Tenda support for firmware updates or advisories. As a temporary workaround, disabling remote management features or applying firewall rules to block access to the affected router's management ports can reduce exposure. Organizations should also consider replacing vulnerable devices with models that receive regular security updates. Implementing network segmentation and intrusion detection systems can help detect and contain exploitation attempts. Finally, maintaining an inventory of network devices and their firmware versions will facilitate rapid response to similar vulnerabilities in the future.