CVE-2025-71020 in AX1806
Summary
by MITRE • 01/16/2026
Tenda AX-1806 v1.0.0.1 was discovered to contain a stack overflow in the security parameter of the sub_4C408 function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted request.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 01/16/2026
The vulnerability identified as CVE-2025-71020 affects the Tenda AX-1806 router firmware version 1.0.0.1 and represents a critical stack overflow condition within the security parameter handling mechanism of the device. This flaw exists within the sub_4C408 function, which processes security-related parameters, creating a potential entry point for malicious actors to disrupt normal device operations. The stack overflow occurs when the firmware fails to properly validate input parameters, allowing an attacker to manipulate memory allocation and execution flow through a specially crafted request. The vulnerability directly impacts the device's stability and availability, as demonstrated by the ability to induce a denial of service condition through carefully constructed payloads.
From a technical perspective, this vulnerability manifests as a classic buffer overflow scenario where insufficient bounds checking permits data to overwrite adjacent memory locations on the stack. The CWE-121 classification applies here, as the vulnerability involves stack-based buffer overflow conditions that can lead to arbitrary code execution or system instability. The specific function sub_4C408 appears to handle security parameter validation without adequate input sanitization, making it susceptible to overflow attacks that can corrupt program execution flow. This type of vulnerability typically arises from improper handling of user-supplied data within embedded systems, where memory constraints and resource limitations often lead to insufficient validation mechanisms.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a foundational security weakness that could potentially enable more sophisticated attacks. When exploited, the stack overflow can cause the router to crash or reboot continuously, effectively rendering the network infrastructure unavailable to legitimate users. The attack surface is particularly concerning given that routers serve as primary network gateways, and their compromise can lead to broader network disruption. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Network Denial of Service) and potentially T1059.007 (Command and Scripting Interpreter: PowerShell) if exploitation leads to command execution capabilities. The DoS condition affects network availability and can be leveraged as part of larger attack campaigns targeting network infrastructure reliability.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from Tenda, as the manufacturer likely has patches addressing the specific stack overflow condition. Network administrators should implement monitoring solutions to detect unusual traffic patterns that might indicate exploitation attempts, particularly around security parameter handling endpoints. Input validation should be strengthened at multiple layers including application-level sanitization and network-level filtering to prevent malformed requests from reaching vulnerable functions. Additionally, network segmentation strategies can limit the impact of successful exploitation by isolating critical network segments. The vulnerability underscores the importance of embedded security testing and proper input validation in IoT devices, as these systems often lack the robust security measures found in traditional computing environments. Organizations should also consider implementing intrusion detection systems specifically configured to identify patterns associated with buffer overflow exploitation attempts.