CVE-2025-7806 in FH451
Summary
by MITRE • 07/19/2025
A vulnerability classified as critical was found in Tenda FH451 1.0.0.9. This vulnerability affects the function fromSafeClientFilter of the file /goform/SafeClientFilter. The manipulation of the argument Go/page leads to stack-based buffer overflow. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 07/24/2025
The vulnerability identified as CVE-2025-7806 represents a critical stack-based buffer overflow in the Tenda FH451 router firmware version 1.0.0.9. This flaw exists within the SafeClientFilter functionality located in the /goform/SafeClientFilter file path, specifically in how the system processes the Go/page argument parameter. The issue stems from inadequate input validation and bounds checking mechanisms that fail to properly handle excessive data input, creating an exploitable condition that allows attackers to overwrite adjacent memory locations on the stack. The vulnerability's classification as critical indicates severe potential impact, as it can lead to arbitrary code execution, system compromise, or complete device takeover. The attack vector is remote, meaning an attacker can exploit this vulnerability without requiring physical access to the device, making it particularly dangerous in networked environments where routers serve as primary gateways for network access. This vulnerability directly maps to CWE-121 Stack-based Buffer Overflow, which is categorized under the Common Weakness Enumeration framework as a fundamental memory safety issue that has been consistently exploited in network device firmware. The disclosure of exploit details in the public domain significantly increases the risk to affected systems, as malicious actors can readily leverage this information to target vulnerable Tenda FH451 devices.
The technical exploitation of this vulnerability occurs through manipulation of the Go/page parameter within the SafeClientFilter function, which processes user-supplied input without adequate sanitization or size validation. When an attacker submits a specially crafted payload containing excessive data to this parameter, the buffer overflow condition is triggered, causing the program to overwrite adjacent stack memory locations. This type of exploitation can lead to several serious consequences including arbitrary code execution, denial of service, or complete system compromise. The stack-based nature of the overflow means that the attacker can potentially overwrite return addresses, function pointers, or other critical stack data structures, allowing for control flow hijacking. This vulnerability aligns with ATT&CK technique T1210: Exploitation of Remote Services, as it represents a remote exploitation vector targeting a network service exposed on the device. The attack can be initiated through HTTP requests to the affected web interface, making it particularly dangerous as it requires no specialized tools or physical access to the device. The specific function fromSafeClientFilter suggests this is part of a security filtering mechanism that should be protecting the device, yet ironically contains a vulnerability that undermines its protective capabilities.
The operational impact of this vulnerability extends beyond individual device compromise to potentially affect entire network infrastructures. When a Tenda FH451 router is successfully exploited, attackers can gain unauthorized access to the network, potentially enabling further lateral movement and persistent access to connected systems. The vulnerability's remote exploitability means that attackers can target multiple devices simultaneously across different geographic locations, creating a scalable threat vector. Network administrators face significant challenges in detecting and mitigating this vulnerability, as the exploitation may not immediately manifest in obvious symptoms, allowing attackers to establish persistent backdoors or exfiltrate data undetected. The affected device operates as a critical network component, serving as the primary gateway for network access, making successful exploitation equivalent to gaining a foothold in the broader network infrastructure. Organizations relying on Tenda FH451 devices for network security may find their protective measures compromised, as the device itself becomes an attack vector rather than a security control. This vulnerability particularly affects enterprise networks, home routers, and IoT deployments where such devices are commonly deployed, creating widespread potential for impact. The exploit's public disclosure increases the probability of automated attacks targeting vulnerable devices, as security researchers and threat actors alike can leverage the published information to develop automated exploitation tools. The vulnerability demonstrates a critical failure in the firmware security testing process, highlighting the need for comprehensive input validation and memory safety checks in network device firmware development. Organizations should consider implementing network segmentation and monitoring to detect potential exploitation attempts, while also prioritizing immediate firmware updates to address this critical vulnerability. The incident underscores the importance of maintaining up-to-date network device firmware and implementing robust security practices to prevent exploitation of known vulnerabilities in network infrastructure components.