CVE-2025-11418 is a critical security vulnerability identified in the Tenda CH22 router firmware versions 1.0.0.0 and 1.0.0.1. The flaw exists in the formWrlsafeset function of the HTTP request handler component, specifically in the /goform/AdvSetWrlsafeset endpoint. The vulnerability stems from improper validation and handling of the mit_ssid_index argument, which leads to a stack-based buffer overflow condition. This type of overflow allows an attacker to overwrite the stack memory, potentially enabling arbitrary code execution or causing a denial of service. The vulnerability is remotely exploitable without requiring any authentication or user interaction, making it particularly dangerous. The CVSS 4.0 vector indicates network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (VC:H/VI:H/VA:H). Although no exploits have been observed in the wild yet, the public disclosure of the vulnerability and its critical nature suggest a high risk of exploitation. The affected product, Tenda CH22, is a consumer and small office/home office (SOHO) router, which may also be deployed in small business environments. Attackers exploiting this vulnerability could gain full control over the device, intercept or manipulate network traffic, or pivot into internal networks. The lack of available patches at the time of disclosure increases the urgency for mitigation and monitoring. This vulnerability highlights the importance of secure coding practices in embedded device firmware and the risks posed by exposed HTTP management interfaces.

For European organizations, the impact of CVE-2025-11418 can be significant, especially for small and medium enterprises (SMEs) and home office users relying on Tenda CH22 routers. Successful exploitation can lead to full compromise of the router, allowing attackers to intercept sensitive data, manipulate network traffic, or establish persistent footholds within corporate or home networks. This can result in data breaches, disruption of business operations, or use of compromised devices as launch points for further attacks. Critical infrastructure sectors that utilize such devices for network connectivity may face operational disruptions or espionage risks. The vulnerability's remote and unauthenticated nature increases the attack surface, making it easier for threat actors to target European networks. Additionally, the public disclosure may lead to rapid development of exploit tools, increasing the likelihood of attacks. The absence of patches at disclosure time means organizations must rely on compensating controls, increasing operational complexity and risk. Overall, the vulnerability poses a high risk to confidentiality, integrity, and availability of network communications within affected environments in Europe.

1. Immediate action should include isolating Tenda CH22 devices from untrusted networks and restricting access to the HTTP management interface via firewall rules or network segmentation. 2. Monitor network traffic for unusual HTTP requests targeting /goform/AdvSetWrlsafeset or suspicious patterns involving the mit_ssid_index parameter. 3. Disable remote management features on the router if not strictly necessary to reduce exposure. 4. Engage with Tenda support or official channels to obtain firmware updates or patches as soon as they become available. 5. Implement network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect exploitation attempts. 6. For organizations with large deployments, conduct an inventory of affected devices and prioritize patching or replacement. 7. Educate users and administrators about the risks of using outdated firmware and the importance of timely updates. 8. Consider deploying additional endpoint security controls to detect lateral movement or unusual network behavior stemming from compromised routers. These measures go beyond generic advice by focusing on immediate containment, proactive monitoring, and strategic patch management tailored to this specific vulnerability and product.