Description

A format string vulnerability exists in the command line interface of AOS-CX that could lead to unauthenticated remote code execution. Successful exploitation of this vulnerability results in the ability to execute arbitrary code as a privileged user on the underlying operating system.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "8.8",
  "pubDate": "2026-09-01T21:18:45.057Z",
  "pubdate": "2026-09-01T21:18:45.057Z",
  "executiveSummary": "A critical format string vulnerability has been identified within the command line interface (CLI) of the AOS-CX operating system. This flaw allows an unauthenticated remote attacker to trigger arbitrary code execution by supplying maliciously crafted input that is improperly processed by a vulnerable function. The vulnerability resides within the user-facing interface, enabling interaction without prior authentication or privilege levels. Successful exploitation grants an attacker full control over the underlying operating system with elevated privileges, posing a severe risk to network infrastructure. Because the vulnerability allows for remote execution, it bypasses standard access control mechanisms, facilitating unauthorized system access, data exfiltration, or complete persistence on the affected device. This security defect necessitates immediate attention due to the high probability of exploitability and the significant impact on confidentiality, integrity, and availability of the managed network hardware.",
  "technicalDetails": "The vulnerability originates from a classic format string error occurring within the command line interface component of AOS-CX. A format string flaw manifests when an attacker-controlled buffer is passed directly to an internal logging or output function (such as printf, syslog, or snprintf) as the format argument, rather than as a data parameter. By injecting format specifiers such as '%x', '%p', or '%n', an attacker can manipulate the stack and memory contents of the application process.\nThe exploitation flow begins with the delivery of a specially crafted packet or command payload to the AOS-CX CLI interface. Because the vulnerable component resides in an unauthenticated network-facing layer, no session establishment or valid credentials are required to initiate the attack. When the CLI parser receives the input, it passes the tainted string to a formatting function without adequate sanitization or format string verification.\nUpon processing the malicious input, the format specifiers allow the attacker to perform several actions: first, the '%x' or '%p' specifiers can be used to leak sensitive memory addresses, which aids in bypassing defensive measures like Address Space Layout Randomization (ASLR). Second, the '%n' specifier provides a powerful primitive that enables the attacker to write arbitrary data to specific memory addresses. By carefully calculating the offset of stack variables and the function's return pointer, the attacker can overwrite critical control flow pointers on the stack.\nBy redirecting execution to a controlled memory location, the attacker can execute arbitrary code payloads. Given the architecture of the AOS-CX system, the process executing the CLI interface typically runs with sufficient system privileges to allow for persistent unauthorized access. Once initial code execution is achieved, the attacker can gain shell access to the underlying operating system. The post-exploitation impact includes the installation of backdoors, full manipulation of network traffic forwarding, modification of routing tables, and comprehensive compromise of the network device. The lack of authentication requirements significantly lowers the barrier for exploitation, making this vulnerability highly accessible to remote threat actors. The vulnerability effectively turns the command line interface into an entry point for system-level takeover, as the input processing logic fails to treat user-provided data as strictly literal content."
}