CVE-2026-24113 is a critical buffer overflow vulnerability identified in the Tenda W20E router firmware version 4.0br_V15.11.0.6. The vulnerability stems from improper handling of the 'nptr' parameter passed into the getMibPrefix function. Specifically, the function uses sprintf to concatenate strings without validating the size of the input, which can lead to a classic stack-based buffer overflow (CWE-120). An attacker who can control the 'nptr' value can exploit this flaw remotely over the network without requiring any authentication or user interaction. Successful exploitation could allow arbitrary code execution, potentially granting full control over the affected device, or cause denial of service by crashing the system. The vulnerability has a CVSS v3.1 base score of 9.8, indicating critical severity with network attack vector, low attack complexity, no privileges required, and no user interaction needed. Although no public exploits or patches are currently available, the high severity and ease of exploitation make this a significant threat. The affected product is a widely used consumer and small business router, which may be deployed in various countries. The lack of patch availability necessitates immediate mitigation through network controls and monitoring until an official fix is released.

The impact of CVE-2026-24113 is severe for organizations using the Tenda W20E router, particularly in environments where these devices are exposed to untrusted networks such as the internet. Exploitation can lead to full compromise of the router, enabling attackers to execute arbitrary code, alter network traffic, intercept sensitive data, or disrupt network availability. This can undermine the confidentiality, integrity, and availability of organizational networks. In critical infrastructure or enterprise environments relying on these routers for connectivity or management, the vulnerability could facilitate lateral movement, persistent access, or serve as a foothold for further attacks. The absence of authentication and user interaction requirements lowers the barrier for attackers, increasing the likelihood of exploitation. The lack of patches further exacerbates the risk, potentially leading to widespread exploitation once public exploits emerge. Organizations may face operational disruptions, data breaches, and reputational damage if this vulnerability is exploited.

1. Immediately isolate Tenda W20E routers from untrusted networks, especially disabling any remote management interfaces accessible from the internet. 2. Implement strict network segmentation to limit access to affected devices only to trusted internal networks. 3. Monitor network traffic for unusual patterns or attempts to exploit the vulnerability, such as malformed packets targeting the getMibPrefix function. 4. Employ intrusion detection/prevention systems (IDS/IPS) with custom signatures to detect exploitation attempts once available. 5. Regularly audit and inventory network devices to identify all instances of the affected router model. 6. Contact Tenda support or vendors for any upcoming patches or firmware updates addressing this vulnerability and apply them promptly once released. 7. As a temporary workaround, consider replacing vulnerable devices with alternative hardware if feasible. 8. Educate network administrators about the vulnerability and ensure they follow best practices for device hardening and monitoring. 9. Restrict physical and logical access to the routers to prevent local exploitation or configuration changes. 10. Maintain up-to-date backups of router configurations to enable rapid recovery if devices are compromised.