CVE-2026-105285 in A3002MU
Summary
by MITRE • 10/05/2026
A security vulnerability has been detected in Totolink A3002MU 1.0.0-B20230403.1455. This affects an unknown function of the file /boafrm/formIpQoS of the component QoS Rule Handler. The manipulation of the argument addQos/comment/entry_name leads to stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit has been disclosed publicly and may be used.
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Analysis
by VulDB Data Team • 10/05/2026
The vulnerability identified in Totolink A3002MU firmware version 1.0.0-B20230403.1455 represents a critical security flaw within the device’s Quality of Service configuration interface, specifically targeting the QoS Rule Handler component. This embedded system, commonly deployed in residential and small business networking environments to manage bandwidth allocation and traffic prioritization, contains an insecure implementation in its web-based management application. The specific point of failure resides in the processing logic for form data submitted via the /boafrm/formIpQoS endpoint. When a user or attacker interacts with this interface to configure network rules, the system fails to adequately validate the length of input provided for the addQos/comment/entry_name parameter before copying it into a fixed-size buffer on the stack. This lack of bounds checking is a fundamental programming error that allows an external actor to overwrite adjacent memory locations beyond the intended boundary of the variable.
From a technical perspective, this flaw classifies as a classic stack-based buffer overflow, which corresponds directly with Common Weakness Enumeration identifier CWE-121. The mechanism involves writing more data into a buffer than it can hold, causing the excess bytes to spill over into neighboring memory spaces on the call stack. In many embedded web servers like BOA, this often leads to the corruption of critical control flow data such as return addresses or saved frame pointers. If an attacker carefully crafts the input payload for the entry_name field, they can potentially overwrite these control structures with malicious code addresses. This manipulation allows the execution flow to be redirected away from normal program operations and into arbitrary shellcode injected by the attacker. The presence of this vulnerability in a network-facing service significantly elevates its severity because it does not require local physical access or prior authentication if the web interface is exposed without strict access controls, although many such devices do enforce basic login requirements which would be required to reach this specific endpoint.
The operational impact of successfully exploiting this stack-based buffer overflow is severe and potentially catastrophic for network integrity. An attacker who achieves remote code execution through this vulnerability gains full control over the embedded Linux environment running on the router. This level of access allows the compromise of Confidentiality, Integrity, and Availability principles across the entire local area network connected to the device. The compromised router can be repurposed as a pivot point for lateral movement into internal servers or workstations that are otherwise protected by perimeter firewalls. Furthermore, attackers may install persistent backdoors, modify DNS settings to redirect traffic to phishing sites, or hijack bandwidth for cryptomining operations. Given that this exploit has been publicly disclosed and is available for use, the window of opportunity for malicious actors is wide open, making devices running this specific firmware version highly susceptible to automated scanning and exploitation campaigns by botnets seeking to expand their infrastructure.
Mitigation strategies must focus on immediate remediation through vendor-supplied updates as well as network-level defensive measures if an update is not yet available or applicable. The primary defense is to upgrade the Totolink A3002MU firmware to a version where this buffer overflow has been patched, ensuring that input validation routines properly check string lengths before memory allocation and copy operations occur. In environments where immediate patching is not feasible, administrators should restrict access to the router’s web management interface by placing it behind an internal firewall or VPN, preventing direct internet exposure of port 80 or 443. Additionally, enabling strong authentication policies and disabling unused services can reduce the attack surface. Security monitoring tools such as Intrusion Detection Systems configured with signatures for known buffer overflow exploits targeting embedded devices should be deployed to detect attempts to manipulate form parameters in suspicious ways. Long-term architectural improvements involve adopting secure coding practices that enforce strict input validation and utilizing memory-safe languages or compiler protections like stack canaries, Address Space Layout Randomization, and Data Execution Prevention where supported by the hardware architecture.