CVE-2026-63586 in IE-SR-2TX-WL
Summary
by MITRE • 08/25/2026
The web-based management interface uses a modified uhttpd server with CGI shell scripts. The HTTP Basic Authentication username, taken directly from the Authorization header without sanitization, is inserted into a shell command string executed via the system() function. By submitting a specially crafted username containing shell metacharacters, an unauthenticated attacker with network access to the device can escape the command context and execute arbitrary commands with root privileges.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability described constitutes a critical remote code execution flaw within the web-based management interface of embedded devices utilizing a modified uhttpd server architecture. This specific implementation relies on Common Gateway Interface shell scripts to handle administrative tasks, creating an attack surface where user-supplied input is directly interpolated into system-level commands without adequate validation or sanitization. The core technical failure lies in how the HTTP Basic Authentication mechanism processes credentials; specifically, the username extracted from the Authorization header is passed verbatim to a shell command execution function, typically system() or exec(), which invokes a standard POSIX-compliant shell interpreter such as sh or bash. Because this process occurs before any authentication check effectively validates the user's identity in a secure context, an unauthenticated attacker can exploit this pre-authentication vector to inject malicious payloads directly into the operating system's command line environment.
From a technical perspective, the flaw is rooted in improper neutralization of special elements used in shell commands, commonly classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command. When the username field contains shell metacharacters such as semicolons, pipes, or backticks, these characters are interpreted by the underlying shell rather than treated as literal string data. For instance, if a user submits a username like admin; rm -rf /, the resulting command executed by the system() function becomes something akin to sh -c "some_script.sh --username=admin; rm -rf /". This allows for complete context escape, bypassing any intended logic within the CGI script and granting direct access to the host operating system. The severity is exacerbated by the fact that uhttpd often runs with elevated privileges or executes scripts as root, meaning successful exploitation results in arbitrary command execution with root-level permissions on the target device.
The operational impact of this vulnerability is severe, enabling an unauthenticated attacker who has network connectivity to the management interface to take full control of the affected system. This can lead to a complete compromise of confidentiality, integrity, and availability. Attackers may install persistent backdoors, exfiltrate sensitive configuration data or user credentials stored on the device, pivot into internal networks if the device serves as a gateway or router, or disrupt services by terminating critical processes. In IoT environments, this often results in the device being recruited into botnets for distributed denial-of-service attacks or used as a foothold for lateral movement within corporate or home networks. The lack of authentication requirement prior to exploitation makes this particularly dangerous, as it requires no valid credentials and can be automated at scale across vulnerable devices exposed on public internet segments.
Mitigation strategies must address both the immediate technical flaw and broader architectural weaknesses. The most effective remediation is to implement strict input validation and output encoding for all user-supplied data before it interacts with system commands. Specifically, developers should avoid using shell interpreters like sh or bash when executing external programs; instead, they should use direct execution functions such as execve() in C-based applications, which do not invoke a shell and thus prevent command injection. If shell scripts are unavoidable due to legacy constraints, all special characters must be escaped or removed from input variables before interpolation into the command string. Additionally, implementing authentication checks earlier in the request processing pipeline ensures that unauthenticated requests are rejected before any sensitive logic is executed. Network-level controls such as restricting access to the management interface via IP whitelisting or placing it behind a secure gateway can also reduce exposure while patches are applied.
This vulnerability aligns with MITRE ATT&CK techniques related to Command and Scripting Interpreter abuse, specifically T1059: Command and Scripting Interpreter, where attackers leverage system utilities to execute arbitrary code. It also reflects common patterns found in CWE-20: Improper Input Validation, highlighting the necessity of treating all external input as untrusted. Organizations managing fleets of embedded devices should prioritize patching these interfaces and consider replacing modified uhttpd instances with more secure web server configurations that enforce strict separation between user data and system commands. Regular security audits focusing on CGI script logic and shell command construction are essential to prevent similar injection vulnerabilities in future development cycles.