CVE-2026-24110 is a buffer overflow vulnerability identified in the Tenda W20E router firmware version V4.0br_V15.11.0.6. The vulnerability stems from the addDhcpRules feature, which processes DHCP rules submitted by users or network devices. Specifically, the function addDhcpRule uses the sscanf function to parse input strings into three variables: dhcpsIndex, dhcpsIP, and dhcpsMac. However, the sscanf call lacks proper bounds checking on the input fields, allowing attackers to send excessively long strings that overflow the buffers allocated for these variables. This memory corruption can lead to undefined behavior, including remote code execution or denial of service. The vulnerability does not require authentication, making it exploitable remotely by attackers who can send crafted DHCP rule data to the device. No patches or firmware updates have been linked yet, and no active exploits have been reported. The vulnerability was reserved in January 2026 and published in March 2026, indicating recent discovery. The absence of a CVSS score necessitates an independent severity assessment based on technical impact and exploitability.

The impact of CVE-2026-24110 is significant for organizations using Tenda W20E routers, especially in environments where these devices are exposed to untrusted networks or the internet. Successful exploitation can lead to remote code execution, allowing attackers to take full control of the router, manipulate network traffic, intercept sensitive data, or pivot into internal networks. Additionally, exploitation could cause denial of service, disrupting network availability and business operations. Given that routers are critical infrastructure components, compromise can undermine confidentiality, integrity, and availability of enterprise networks. The lack of authentication requirement and ease of triggering the vulnerability increase the risk profile. Organizations relying on these devices for home or small office networking are particularly vulnerable, as these devices often lack advanced security monitoring. The absence of known exploits currently provides a window for proactive mitigation before widespread attacks occur.

Organizations should immediately inventory their network to identify Tenda W20E routers running the vulnerable firmware version V4.0br_V15.11.0.6. Since no official patches are currently available, network administrators should implement compensating controls such as restricting access to router management interfaces and DHCP services to trusted internal networks only. Deploy network-level filtering to block suspicious or malformed DHCP traffic, especially from untrusted sources. Monitor network traffic for unusual DHCP rule submissions and anomalous router behavior. Engage with Tenda support channels to obtain firmware updates or security advisories. Consider replacing vulnerable devices with models from vendors with stronger security track records if timely patches are not forthcoming. Additionally, apply network segmentation to limit the impact of potential router compromise. Regularly update router firmware once patches become available and validate the integrity of network devices through security assessments.