CVE-2025-57062 is a high-severity vulnerability identified in the Tenda G3 router firmware version 3.0br_V15.11.0.17. The flaw is a stack-based buffer overflow occurring in the delDhcpIndex parameter within the formDelDhcpRule function. This vulnerability is triggered when an attacker sends a specially crafted request that manipulates the delDhcpIndex parameter, causing the stack overflow. The consequence of this overflow is a Denial of Service (DoS) condition, where the router may crash or become unresponsive, disrupting network connectivity. The vulnerability is remotely exploitable over the network without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The vulnerability is classified under CWE-121, which corresponds to stack-based buffer overflows, a common and critical class of memory corruption errors. Although no exploits have been reported in the wild yet, the CVSS score of 7.5 reflects the high risk due to ease of exploitation and the potential for significant availability impact. No patches or fixes have been linked yet, which suggests that affected users should be vigilant and consider mitigation strategies until an official update is released.

For European organizations, this vulnerability poses a significant risk to network infrastructure relying on Tenda G3 routers. A successful exploit can cause network outages by crashing routers, leading to loss of internet connectivity and disruption of business operations. This is particularly critical for organizations with remote or branch offices using these devices as primary network gateways. The DoS condition could also be leveraged as part of a larger attack campaign to cause widespread disruption or as a diversion for other malicious activities. Since the vulnerability does not compromise confidentiality or integrity directly, the primary impact is on availability, which can still result in financial losses, reputational damage, and operational delays. Critical infrastructure sectors, including healthcare, finance, and government agencies in Europe, could be especially vulnerable if these routers are deployed in their networks.

1. Immediate network segmentation: Isolate Tenda G3 routers from critical network segments to limit the impact of a potential DoS attack. 2. Access control: Restrict access to router management interfaces to trusted IP addresses only, preferably via VPN or secure management channels. 3. Monitor network traffic: Implement intrusion detection systems (IDS) and anomaly detection to identify unusual requests targeting the delDhcpIndex parameter. 4. Disable or limit DHCP rule modification interfaces if not required, reducing the attack surface. 5. Regular firmware audits: Continuously check for firmware updates from Tenda and apply patches promptly once available. 6. Incident response planning: Prepare for potential DoS events by having failover internet connections or redundant network paths. 7. Vendor engagement: Engage with Tenda support to obtain timelines for patches and request interim mitigations or workarounds.