CVE-2025-11423 is a critical security vulnerability identified in the Tenda CH22 router firmware version 1.0.0.1. The flaw exists in the formSafeEmailFilter function located in the /goform/SafeEmailFilter endpoint, specifically due to improper validation and handling of the 'page' argument. This improper handling leads to memory corruption, which can be exploited remotely without requiring authentication or user interaction. The vulnerability allows attackers to manipulate the router’s memory, potentially enabling arbitrary code execution, complete system compromise, or denial of service conditions. The vulnerability is remotely exploitable over the network, increasing its severity. The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P) reflects that no privileges or user interaction are required, and the impact on confidentiality, integrity, and availability is high. While no active exploitation in the wild has been reported, the public availability of exploit code significantly raises the risk of imminent attacks. The vulnerability affects a specific firmware version, making it critical for users of Tenda CH22 devices to verify their firmware and apply updates once released. The lack of current patches or mitigations from the vendor increases the urgency for network-level defenses and monitoring. Given the widespread use of Tenda routers in small to medium enterprises and home environments, this vulnerability poses a significant risk to network security and data protection.

For European organizations, the impact of CVE-2025-11423 can be severe. Successful exploitation could lead to unauthorized remote control of affected routers, enabling attackers to intercept, manipulate, or disrupt network traffic. This compromises the confidentiality and integrity of sensitive communications and can lead to lateral movement within corporate networks. The availability of network services may also be disrupted due to denial of service conditions triggered by memory corruption. Organizations relying on Tenda CH22 routers for critical infrastructure or business operations could face operational downtime, data breaches, and potential regulatory penalties under GDPR if personal data is exposed. The public availability of exploit code increases the likelihood of targeted attacks, especially against sectors with high-value data or critical services. Additionally, compromised routers could be leveraged as entry points for broader cyber espionage or ransomware campaigns. The risk is heightened in environments with limited network segmentation or outdated security controls, common in small and medium enterprises across Europe.

1. Immediately identify and inventory all Tenda CH22 devices running firmware version 1.0.0.1 within the network. 2. Monitor vendor communications closely for official patches or firmware updates addressing CVE-2025-11423 and apply them promptly upon release. 3. Until patches are available, restrict external and internal network access to the /goform/SafeEmailFilter endpoint using firewall rules or access control lists to prevent exploitation. 4. Implement network segmentation to isolate vulnerable devices from critical systems and sensitive data repositories. 5. Deploy intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics capable of detecting exploitation attempts targeting this vulnerability. 6. Conduct regular network traffic analysis to identify anomalous requests to the vulnerable endpoint. 7. Educate IT and security teams about the vulnerability and the importance of rapid response. 8. Consider temporary replacement or upgrade of vulnerable devices if patching is delayed or unavailable. 9. Enforce strong network perimeter defenses and limit administrative access to router management interfaces. 10. Maintain up-to-date backups and incident response plans to mitigate potential damage from exploitation.