CVE-2026-94954 in Firmware
Summary
by MITRE • 09/29/2026
A stack-based buffer overflow vulnerability exists in the web management interface of TOTOLINK N150RT (NTR150) firmware V3.4.0-B20201030. It is reachable through the route /boafrm/formFilter (access-control / URL filter configuration handler) and is triggered by the url request parameter when the addFilterUrl (or addFilterUrlFlag) action flag is set.
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified in TOTOLINK N150RT firmware version V3.4.0-B20201030 represents a critical security flaw within the device's web management interface, specifically affecting the access control and URL filtering subsystems. This stack-based buffer overflow is located at the endpoint /boafrm/formFilter, which serves as the handler for configuring filter rules. The root cause of this vulnerability lies in the improper handling of user-supplied input when processing the url request parameter during an addFilterUrl or addFilterUrlFlag action. In a typical web management interface, such parameters are expected to be validated and sanitized before being copied into fixed-size stack buffers. However, in this specific firmware version, the application fails to perform adequate bounds checking on the length of the input string provided via the url parameter. Consequently, when an attacker supplies a payload exceeding the allocated buffer size, the excess data overwrites adjacent memory locations on the call stack, including return addresses and saved frame pointers. This type of flaw is classically categorized under CWE-121, which denotes a stack-based buffer overflow where local variables are written beyond their intended boundaries due to insufficient validation of input length or structure.
From an operational perspective, this vulnerability poses a severe risk because the web management interface often runs with elevated privileges relative to other services on the router. If successfully exploited, an attacker can achieve arbitrary code execution within the context of the vulnerable process. This typically allows for remote command injection, enabling the compromise of the entire network infrastructure behind the router. The impact extends beyond simple data corruption; it facilitates a complete takeover of the device's control plane. Attackers could install persistent backdoors, redirect traffic through malicious proxies for man-in-the-middle attacks, or use the compromised device as part of a botnet. This aligns with MITRE ATT&CK techniques such as T1059 Command and Scripting Interpreter, where an attacker executes commands on a remote system, and potentially T1486 Data Encrypted for Impact if used to deploy ransomware or other destructive payloads across the local network segment. The accessibility of this vector through standard HTTP requests makes it particularly dangerous in environments where the management interface is exposed to untrusted networks or lacks strong authentication mechanisms.
Mitigation strategies must address both immediate remediation and long-term security posture improvements. The primary solution involves upgrading the firmware to a version released by TOTOLINK that includes patches for this buffer overflow, ensuring that input validation routines are correctly implemented to truncate or reject oversized url parameters. In scenarios where an upgrade is not immediately feasible, network-level controls should be employed to restrict access to the management interface exclusively from trusted IP addresses using firewall rules. Additionally, implementing strict authentication policies and disabling remote administration features can significantly reduce the attack surface. Security monitoring tools should also be configured to detect anomalous HTTP requests containing unusually long url parameters directed at the /boafrm/formFilter endpoint, which may indicate an active exploitation attempt. Regular vulnerability assessments and penetration testing of IoT devices are essential to identify similar implementation flaws in other network components before they can be leveraged by adversaries.