CVE-2025-45514 is a stack overflow vulnerability identified in the Tenda FH451 router firmware version 1.0.0.9, specifically within the function named frmL7ImForm. A stack overflow occurs when a program writes more data to a buffer located on the stack than what is actually allocated, potentially overwriting adjacent memory and leading to unpredictable behavior. This vulnerability is classified under CWE-121, which refers to stack-based buffer overflows. According to the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N), the vulnerability can be exploited remotely over the network without requiring any privileges or user interaction, making it relatively easy to exploit. The impact includes limited confidentiality and integrity loss but no direct impact on availability. The absence of patches or known exploits in the wild suggests that this vulnerability is newly disclosed and may not yet be actively exploited. However, the presence of a stack overflow in network-facing firmware is a significant concern because it could potentially be leveraged for remote code execution or other malicious activities if combined with additional exploitation techniques. The lack of detailed vendor or product information beyond the Tenda FH451 model limits the scope of the analysis but confirms the vulnerability is specific to this router model and firmware version.

For European organizations, the impact of this vulnerability depends largely on the deployment of Tenda FH451 routers within their networks. If these devices are used in enterprise or critical infrastructure environments, exploitation could lead to unauthorized access or manipulation of network traffic, potentially compromising sensitive data confidentiality and integrity. Although the CVSS score indicates no direct availability impact, attackers could leverage this vulnerability as a foothold for further attacks, including lateral movement or espionage. Small and medium-sized enterprises (SMEs) or home office setups using this router model may be at risk of having their network security compromised, which could indirectly affect business operations. Given the router’s role as a network gateway, successful exploitation could also facilitate man-in-the-middle attacks or interception of communications. The absence of known exploits in the wild currently reduces immediate risk but does not eliminate the potential for future exploitation, especially as exploit code may be developed following public disclosure.

Organizations should first identify whether Tenda FH451 routers running firmware version 1.0.0.9 are present in their network environments. Since no official patches or updates are currently available, immediate mitigation steps include isolating affected devices from critical network segments and restricting remote management access to trusted IP addresses only. Network-level protections such as intrusion detection and prevention systems (IDS/IPS) should be configured to monitor and block suspicious traffic targeting the vulnerable function or unusual packet patterns. Employing network segmentation can limit the potential impact if exploitation occurs. Additionally, organizations should monitor vendor communications for firmware updates or security advisories and apply patches promptly once released. As a longer-term measure, consider replacing vulnerable devices with models that have a stronger security track record and ongoing vendor support. Regular network traffic analysis and anomaly detection can help identify exploitation attempts early.