CVE-2025-70746 is a stack overflow vulnerability identified in the Tenda AX-1806 router firmware version 1.0.0.1. The flaw exists in the handling of the timeZone parameter within the fromSetSysTime function. A stack overflow occurs when the function processes a specially crafted request containing malicious input in the timeZone parameter, leading to memory corruption. This vulnerability can be exploited remotely without authentication by sending a crafted request to the router's management interface, causing the device to crash or reboot, resulting in a Denial of Service (DoS). While no exploits have been reported in the wild and no patches have been released yet, the vulnerability poses a risk to network availability. The affected device is typically used in home and small office environments, where disruption can impact internet connectivity and network services. The lack of authentication requirement and the straightforward nature of the attack increase the risk profile. However, exploitation requires network access to the device, which may be limited by network segmentation or firewall rules. The vulnerability does not appear to allow code execution or data theft but can cause significant operational disruption through device unavailability.

For European organizations, the primary impact of CVE-2025-70746 is on network availability. A successful attack can cause routers to crash or reboot, interrupting internet access and internal network connectivity. This can disrupt business operations, particularly for small and medium-sized enterprises (SMEs) and remote workers relying on Tenda AX-1806 routers. The DoS could affect VoIP communications, cloud service access, and other critical online services. While the vulnerability does not directly compromise confidentiality or integrity, the loss of availability can lead to productivity losses and potential secondary security risks if fallback or recovery procedures are inadequate. Organizations with limited IT support or those that do not regularly update firmware may be more vulnerable. The absence of known exploits reduces immediate risk, but the potential for future exploitation remains. Additionally, the vulnerability could be leveraged as part of a broader attack campaign targeting consumer-grade networking equipment to cause widespread disruption.

1. Immediately restrict access to the router's management interface by limiting it to trusted internal networks and disabling remote management where possible. 2. Implement network segmentation to isolate critical systems from consumer-grade routers like the Tenda AX-1806. 3. Monitor network traffic for unusual or malformed requests targeting router management services, especially those involving time synchronization or timezone settings. 4. Educate users and IT staff about the vulnerability and encourage vigilance for signs of router instability or unexpected reboots. 5. Regularly check the vendor's website and security advisories for firmware updates or patches addressing this vulnerability and apply them promptly once available. 6. Consider replacing vulnerable devices with models from vendors with stronger security track records if timely patches are not forthcoming. 7. Employ network-level DoS protection mechanisms to mitigate the impact of potential attacks exploiting this vulnerability. 8. Maintain up-to-date backups of router configurations to enable rapid recovery after a DoS event.