CVE-2026-15485 in TEW-821DAP
Summary
by MITRE • 07/12/2026
A flaw has been found in TRENDnet TEW-821DAP 1.11B03. The impacted element is the function sub_43F2C4 of the file /goform/tools_nslookup of the component DNS Lookup Handler. This manipulation of the argument nslookup_target/dns_server causes os command injection. The attack can be initiated remotely. The vendor explains: "We are unable to confirm the existence of the vulnerabilities for (...) TEW-821DAP (v1.0R) as these items have been EOL. " This vulnerability only affects products that are no longer supported by the maintainer.
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Analysis
by VulDB Data Team • 07/12/2026
The vulnerability identified in TRENDnet TEW-821DAP version 1.11B03 represents a critical command injection flaw within the device's web interface administration functionality. This issue manifests in the sub_43F2C4 function located within the /goform/tools_nslookup file, which serves as the DNS Lookup Handler component. The vulnerability stems from inadequate input validation and sanitization of user-supplied parameters, specifically the nslookup_target and dns_server arguments that are processed by this function. When these parameters are manipulated by an attacker, they can be exploited to inject arbitrary operating system commands directly into the device's underlying shell environment.
The technical exploitation of this vulnerability occurs through remote manipulation of the web-based administration interface. Attackers can construct malicious payloads that leverage the insufficient input validation to execute unauthorized commands on the affected device. This command injection capability allows for complete compromise of the device's operational environment, potentially enabling attackers to gain persistent access, modify device configuration, or escalate privileges within the system. The vulnerability directly maps to CWE-78, which describes improper neutralization of special elements used in OS commands, and represents a classic example of how insecure input handling can lead to arbitrary code execution.
The operational impact of this vulnerability extends beyond simple device compromise, as it provides attackers with full control over the network device's functionality. This includes potential access to internal network resources, ability to redirect DNS queries, modification of network settings, and establishment of persistent backdoors. The affected device operates as a wireless access point, making it a critical component in network infrastructure where such compromise could lead to broader network infiltration or denial of service conditions. According to ATT&CK framework, this vulnerability aligns with T1059.001 (Command and Scripting Interpreter: PowerShell) and T1068 (Exploitation for Privilege Escalation) techniques, as it enables arbitrary command execution and potential privilege escalation within the device's operating system.
The vendor's response regarding end-of-life status for this product creates a particularly concerning scenario where a critical security vulnerability remains unpatched and unsupported. This situation exemplifies the common problem of legacy network equipment continuing to operate in production environments despite lack of security updates, leaving organizations vulnerable to exploitation. The absence of vendor support for this specific model means that organizations utilizing these devices face limited remediation options, forcing them to either replace the hardware or implement network segmentation and monitoring measures to detect potential exploitation attempts. Organizations should consider implementing network access controls to limit exposure of unsupported devices and establish monitoring protocols for unusual command execution patterns in their network infrastructure.
The vulnerability demonstrates how even seemingly simple administrative functions can contain critical security flaws when proper input validation is not implemented. The device's web interface architecture appears to directly pass user-supplied DNS lookup parameters to system commands without adequate sanitization, creating an attack surface that allows for complete system compromise. This flaw represents a fundamental security weakness in the device's design and implementation that could be exploited by attackers with minimal technical expertise, making it particularly dangerous in environments where such devices are deployed without proper network segmentation or monitoring controls.