CVE-2026-86151 in CP3
Summary
by MITRE • 09/06/2026
A vulnerability was detected in Tenda CP3 27.5.57.101. The affected element is the function sub_2F77E8 of the file Apis/system.c of the component Network Configuration Management. Performing a manipulation results in os command injection. The attack may be initiated remotely.
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Analysis
by VulDB Data Team • 09/06/2026
The vulnerability identified within Tenda CP3 firmware version 27.5.57.101 represents a critical security flaw located in the Network Configuration Management subsystem, specifically within the sub_2F77E8 function of the Apis/system.c source file. This component is responsible for handling network configuration requests, which are often exposed to external networks via web interfaces or API endpoints. The presence of this vulnerability indicates that user-supplied input processed by this specific function is not adequately sanitized before being passed to underlying operating system commands. Consequently, an attacker can inject arbitrary shell commands into the application context, leading to a remote code execution scenario with the privileges of the compromised service account.
This flaw aligns directly with CWE-78, which defines Improper Neutralization of Special Elements used in an OS Command, commonly known as OS command injection. The technical mechanism involves the concatenation or interpolation of unsanitized user input into system-level commands such as those executed via functions like system() or popen(). Because the vulnerability resides in a network-facing component and can be triggered remotely, it falls under the ATT&CK technique T1059, specifically Command and Scripting Interpreter. This classification highlights that an adversary could leverage this entry point to execute arbitrary scripts or commands on the target device without requiring prior authentication if the affected endpoint is accessible over the internet, or with low-privilege credentials if local access is required but still poses a severe risk due to the potential for privilege escalation through subsequent exploitation steps.
The operational impact of this vulnerability is profound, as it allows an attacker to gain full control over the IoT device's operating system. Once command injection is achieved, the attacker can perform actions such as reading sensitive configuration files, modifying network settings to redirect traffic, installing persistent backdoors, or using the compromised device as a pivot point for further attacks within the local network segment. In the context of Internet of Things devices like routers and access points, this often leads to the formation of botnets used for distributed denial-of-service attacks or data exfiltration campaigns. The remote nature of the attack vector means that no physical proximity is required, significantly expanding the attack surface and increasing the likelihood of successful exploitation by automated scanning tools targeting known vulnerable firmware versions.
Mitigation strategies must prioritize immediate patching to a version where this vulnerability has been remediated through proper input validation and output encoding techniques. Developers should implement strict allow-lists for acceptable inputs in network configuration parameters, ensuring that only expected data types and formats are processed. Additionally, employing principle of least privilege is essential; the service running sub_2F77E8 should operate with minimal system permissions to limit the blast radius if an injection occurs. For organizations unable to immediately patch, deploying web application firewalls or network intrusion detection systems configured to detect common command injection patterns can provide a layer of defense-in-depth. Regular firmware audits and monitoring for unusual outbound connections from IoT devices are also recommended to identify potential compromises early in the kill chain.