CVE-2025-44176 is a remote code execution (RCE) vulnerability affecting the Tenda FH451 router firmware version 1.0.0.9. The vulnerability resides in the formSafeEmailFilter function, which is likely responsible for sanitizing or processing email-related input. The weakness is classified under CWE-77, indicating an OS command injection flaw. This means that an attacker can craft malicious input to the vulnerable function, which is then executed by the system shell without proper sanitization or validation. The vulnerability has a CVSS v3.1 base score of 6.5, reflecting a medium severity level. The vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N indicates that the attack can be performed remotely over the network without any privileges or user interaction, with low attack complexity. The impact affects confidentiality and integrity, allowing an attacker to execute arbitrary commands remotely, potentially leading to unauthorized access or control over the device. However, availability is not impacted. There are no known exploits in the wild at the time of publication, and no patches have been released yet. The vulnerability was reserved on April 22, 2025, and published on May 12, 2025. The lack of vendor or product details beyond the Tenda FH451 model limits the scope of affected versions, but it is clear that the firmware version 1.0.0.9 is vulnerable. This vulnerability poses a significant risk to the security of networks relying on this router model, as successful exploitation could allow attackers to compromise the device and potentially pivot to internal networks or intercept sensitive communications.

For European organizations using Tenda FH451 routers, this vulnerability could lead to unauthorized remote code execution, enabling attackers to gain control over network infrastructure devices. This compromises the confidentiality and integrity of network traffic and device configurations. Attackers could manipulate routing, intercept or redirect data, or use the compromised device as a foothold for further attacks within the corporate network. Given that no authentication or user interaction is required, the threat is particularly severe in environments where these routers are exposed to untrusted networks or the internet. The absence of a patch increases the risk window, potentially allowing attackers to develop exploits. This could impact sectors with high reliance on network security such as finance, healthcare, and critical infrastructure in Europe. Additionally, compromised routers could be used in botnets or for launching distributed denial-of-service (DDoS) attacks, affecting service availability indirectly.

1. Immediate network segmentation: Isolate Tenda FH451 routers from critical network segments and restrict their exposure to untrusted networks, especially the internet. 2. Access control: Implement strict firewall rules to limit inbound traffic to management interfaces of these routers. 3. Monitoring and detection: Deploy network intrusion detection systems (NIDS) to identify suspicious command injection attempts or anomalous traffic patterns targeting the router. 4. Vendor engagement: Engage with Tenda support or vendor channels to obtain official patches or firmware updates as soon as they become available. 5. Temporary workaround: If possible, disable or restrict the vulnerable formSafeEmailFilter functionality or related services until a patch is released. 6. Device replacement: For high-risk environments, consider replacing affected routers with models from vendors with timely security support. 7. Incident response readiness: Prepare for potential exploitation by updating incident response plans to include detection and remediation steps for this vulnerability. 8. Regular firmware audits: Maintain an inventory of network devices and their firmware versions to quickly identify vulnerable units.