CVE-2026-116506 in A950RG
Summary
by MITRE • 10/26/2026
A vulnerability was determined in TOTOLINK A950RG 4.1.2cu.5268_B20221104. Affected is the function apmib_set of the file firewall.so. This manipulation causes command injection. The attack may be initiated remotely. The exploit has been publicly disclosed and may be utilized.
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Analysis
by VulDB Data Team • 10/26/2026
The vulnerability identified in TOTOLINK A950RG firmware version 4.1.2cu.5268_B20221104 represents a critical security flaw within the device's web management interface, specifically located in the apmib_set function of the firewall.so shared library. This component is responsible for handling configuration updates related to network firewall rules and settings. The core technical issue stems from improper input validation and sanitization mechanisms when processing user-supplied data passed through this API endpoint. Because the application fails to adequately filter special characters or command delimiters, an attacker can inject arbitrary operating system commands into the underlying shell environment that executes these configuration changes. This class of defect is formally categorized under CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as OS Command Injection. The flaw allows for a complete bypass of intended security controls by leveraging the elevated privileges typically held by web server processes on embedded Linux devices.
The operational impact of this vulnerability is severe due to its remote exploitable nature and the public availability of proof-of-concept exploits. An unauthenticated attacker located anywhere on the internet can interact with the vulnerable endpoint without needing valid credentials, provided they know or can guess the target IP address. By crafting a malicious HTTP request containing shell metacharacters such as semicolons, pipes, or backticks within specific configuration parameters, an adversary can achieve remote code execution (RCE) under the context of the web server user, which is often root on many embedded routers. This capability effectively grants full control over the device, allowing the attacker to modify network configurations, exfiltrate sensitive data such as Wi-Fi passwords and connected client information, or pivot into other devices within the local area network. The public disclosure of exploits significantly lowers the barrier for entry, enabling automated scanning tools and opportunistic attackers to compromise vulnerable instances at scale.
From a threat intelligence perspective, this vulnerability aligns with MITRE ATT&CK techniques related to Initial Access via Exploitation of Remote Services (T1190) and Execution via Command and Script Interpreter (T1059). The ability to execute arbitrary commands facilitates subsequent lateral movement within the network, potentially leading to data exfiltration or deployment of malware such as botnet agents. Given that TOTOLINK devices are frequently deployed in residential and small business environments with weak default security postures, this vulnerability poses a substantial risk to broader internet infrastructure stability if left unpatched. The persistence of such flaws highlights the challenges inherent in embedded device development where rigorous secure coding practices may be overlooked during rapid firmware release cycles.
Mitigation strategies must prioritize immediate remediation through vendor-provided updates. Administrators should check for and install any newer firmware versions released by TOTOLINK that address this specific command injection flaw in the firewall.so module. In cases where patching is not immediately feasible, network-level controls can provide temporary relief. This includes restricting access to the router's management interface via IP whitelisting on firewalls or VLAN segmentation to ensure only trusted internal hosts can reach the administrative ports. Additionally, disabling remote administration features if they are not strictly required reduces the attack surface exposed to external networks. Security teams should also monitor network traffic for anomalous outbound connections from IoT devices, which may indicate successful exploitation and subsequent command execution attempts. Regular vulnerability scanning of connected assets is recommended to detect exposure before active exploitation occurs in the wild.