CVE-2025-7423 in O3V2
Summary
by MITRE • 07/11/2025
A vulnerability classified as critical was found in Tenda O3V2 1.0.0.12(3880). Affected by this vulnerability is the function formWifiMacFilterSet of the file /goform/setWrlFilterList of the component httpd. The manipulation of the argument macList leads to stack-based buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 07/11/2025
This critical vulnerability exists in the Tenda O3V2 router firmware version 1.0.0.12(3880) within the httpd web server component. The flaw resides in the formWifiMacFilterSet function located in the /goform/setWrlFilterList file, which handles wireless MAC address filtering operations. The vulnerability manifests as a stack-based buffer overflow when processing the macList parameter, creating a significant security risk that can be exploited remotely without requiring physical access or authentication. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which represents a classic and dangerous class of memory corruption flaws that can lead to arbitrary code execution or system crashes. The attack vector is particularly concerning as it operates over the network, allowing remote exploitation from any location with internet connectivity to the affected device. The public disclosure of exploit code further amplifies the severity of this vulnerability, as it removes the barrier to entry for potential attackers who may not possess advanced exploitation capabilities.
The technical implementation of this vulnerability involves the improper handling of user-supplied input through the macList argument in the wireless filtering configuration endpoint. When an attacker sends a specially crafted request containing an excessively long macList parameter to the vulnerable web service, the application fails to properly validate or limit the input length before copying it into a fixed-size stack buffer. This buffer overflow condition can overwrite adjacent memory locations including return addresses, function pointers, or other critical control data structures. The stack-based nature of the overflow means that the attacker can potentially manipulate the program's execution flow to redirect control to malicious code injected into the buffer, or alternatively cause a denial of service through stack corruption that results in application crashes or reboots. Given that this operates within the httpd web server component, successful exploitation could provide attackers with complete control over the router's network operations and potentially enable them to establish persistent access or use the device as a pivot point for attacking other systems on the local network.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass a comprehensive compromise of network security infrastructure. An attacker who successfully exploits this vulnerability can gain unauthorized access to the router's administrative interface, potentially enabling them to modify network configurations, disable security features, or establish persistent backdoors. The compromised router could then serve as a platform for conducting man-in-the-middle attacks, DNS poisoning, or as a launching point for broader network infiltration efforts. This aligns with ATT&CK technique T1071.004 Application Layer Protocol: DNS where compromised network devices can be used to manipulate DNS queries and redirect traffic. The vulnerability's remote exploitability means that attackers do not need physical access to the device, making it particularly dangerous for enterprise environments where network security devices are often not properly segmented or monitored. The widespread deployment of Tenda O3V2 devices in residential and small business environments increases the potential attack surface significantly, as these devices typically lack the robust security monitoring and patch management processes found in enterprise environments.
Mitigation strategies for this vulnerability require immediate action from affected organizations and end users. The primary and most effective mitigation is to update the router firmware to the latest version available from Tenda, which should contain the necessary patches to address the buffer overflow condition. Network administrators should implement network segmentation and access control measures to limit the potential impact of a compromised device, including restricting access to the router's web interface to trusted IP addresses only. Additional defensive measures include deploying network monitoring tools to detect unusual traffic patterns that might indicate exploitation attempts, implementing intrusion detection systems that can identify known exploit signatures, and conducting regular vulnerability assessments of network infrastructure to identify similar issues in other devices. The vulnerability also highlights the importance of firmware security practices and the need for manufacturers to implement proper input validation and bounds checking in embedded web server implementations. Organizations should also consider disabling unnecessary services and features on network devices, particularly those that expose web interfaces to external networks, and maintain comprehensive asset inventories to ensure all network-connected devices are properly managed and patched according to their security risk profiles.