CVE-2025-7793 in FH451
Summary
by MITRE • 07/18/2025
A vulnerability classified as critical has been found in Tenda FH451 1.0.0.9. Affected is the function formWebTypeLibrary of the file /goform/webtypelibrary. The manipulation of the argument webSiteId leads to stack-based buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 07/23/2025
The vulnerability identified as CVE-2025-7793 represents a critical stack-based buffer overflow flaw within the Tenda FH451 router firmware version 1.0.0.9. This security weakness resides in the formWebTypeLibrary function located within the /goform/webtypelibrary file path, making it a significant target for remote exploitation. The vulnerability specifically manifests when the webSiteId argument is manipulated, allowing attackers to exceed the bounds of a stack-allocated buffer and potentially execute arbitrary code on the affected device. The remote attack vector means that malicious actors can exploit this flaw without requiring physical access to the router, making it particularly dangerous for networked environments. This vulnerability has been publicly disclosed, increasing the risk of widespread exploitation across affected installations. The flaw falls under the CWE-121 category of stack-based buffer overflow, which is classified as a fundamental memory safety issue that has been documented in numerous security advisories and represents one of the most common attack vectors in embedded systems. The attack surface is further expanded by the fact that this is a web-based interface vulnerability, meaning that exploitation can occur through standard web browser interactions or automated attack tools targeting the router's web management interface.
The technical implementation of this buffer overflow vulnerability demonstrates a classic stack corruption scenario where insufficient input validation allows an attacker to overwrite adjacent stack memory locations. When the webSiteId parameter is processed by the formWebTypeLibrary function, the application fails to properly bounds-check the input before copying it into a fixed-size buffer on the stack. This allows an attacker to inject malicious data that overflows the buffer and potentially overwrites the return address of the function, enabling arbitrary code execution. The stack-based nature of this vulnerability means that the attack can be reliably executed through carefully crafted input parameters, and the fact that this occurs in a web management interface makes it particularly accessible to attackers who may be scanning for vulnerable devices on the internet. The exploitation process typically involves sending a specially crafted HTTP request containing an oversized webSiteId parameter to the router's management interface, which triggers the buffer overflow condition. This vulnerability represents a serious threat to network security as it can potentially allow attackers to gain full control of the router, modify network configurations, redirect traffic, or establish persistent access points within the network infrastructure.
The operational impact of CVE-2025-7793 extends beyond simple remote code execution, as it fundamentally compromises the security posture of any network that contains affected Tenda FH451 devices. Once exploited, attackers can gain complete administrative control over the router, potentially leading to man-in-the-middle attacks, DNS poisoning, traffic interception, or the establishment of backdoors for continued access. The vulnerability's classification as critical by security vendors indicates that it can be exploited automatically by malware or automated scanning tools, making it particularly dangerous for unpatched networks. Organizations and individuals with affected devices face significant risks including data breaches, network disruption, and potential use as launching points for attacks on other networked systems. The public disclosure of this exploit increases the likelihood of widespread compromise across networks, as threat actors can readily develop and deploy automated tools to scan for and exploit vulnerable devices. Network administrators must consider that this vulnerability can be leveraged to compromise not just individual devices but entire network infrastructures, particularly in environments where multiple Tenda routers are deployed without proper security monitoring or patch management procedures.
Mitigation strategies for CVE-2025-7793 should prioritize immediate firmware updates from Tenda, as this is the most effective method to address the underlying buffer overflow vulnerability. Network administrators should implement network segmentation and access controls to limit exposure of affected devices to external networks, while also deploying intrusion detection systems to monitor for exploitation attempts. The implementation of web application firewalls and input validation measures can provide additional protection layers, though these are secondary to firmware updates. Security teams should conduct comprehensive network scans to identify all instances of the affected Tenda FH451 firmware versions and prioritize their remediation. The vulnerability's classification under ATT&CK technique T1210 (Exploitation of Remote Services) and CWE-121 indicates that defensive measures should include regular vulnerability assessments and network monitoring for suspicious HTTP traffic patterns. Organizations should also consider implementing network access control policies that restrict administrative access to network devices and establish procedures for rapid response to security incidents involving router compromise. Due to the public availability of exploitation tools, immediate action is required to secure affected systems, as the window for exploitation is likely to be extended by the widespread availability of automated attack scripts targeting this specific vulnerability.