External risk intelligence

Flyto2 Core Arbitrary File Write Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 10.0)

CVE-2026-67429

Flyto2 Core is a library and execution kernel for automation and AI-agent workflows. While these components may be integrated into internet-facing applications, they are typically backend processing engines rather than public-facing services by design. Public reachability depends heavily on how the developer implements and exposes the automation workflows in a specific deployment.

Path Traversal

Halo Surface Signal: 3 out of 5 — possibly public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability impacts Flyto2 Core, a kernel for automation and AI-agent workflows. The issue allows attackers to write malicious files to arbitrary locations on a system, potentially leading to unauthorized data modification or system compromise. The main concern is confirming relevance and exposure due to the backend nature of this technology.

Unrestricted file writing capability in workflow kernel.
Potential for system compromise and data manipulation.
Confirm Flyto2 Core usage and exposure within your environment.

Attack Path

How an attacker could exploit the issue

An attacker could exploit this vulnerability by tricking the Flyto2 Core into writing arbitrary data to any file the process has write access to, potentially overwriting critical system files or injecting malicious code. This is possible because the `image.download` module does not properly validate the output directory, allowing attacker-controlled data to be written to any location.

No authentication or user interaction needed.
Attacker-controlled data written to arbitrary paths.
Remote code execution or system disruption.

Live Threat

Current exploitation, exposure, and threat context

When supported by the advisory, attacker-controlled response bytes could be written to arbitrary filesystem paths accessible to the process, potentially impacting system integrity and service behavior.

Arbitrary file write to accessible paths.
Exploitation via crafted response bytes.
System integrity and service disruption.

Operational Fix

Recommended remediation, mitigation, and detection steps

Application owners and infrastructure teams are likely responsible for addressing this vulnerability in Flyto2 Core, an execution kernel for automation and AI-agent workflows. The first practical step is to identify all instances of Flyto2 Core, determine their exposure and criticality, and then confirm the accountable owners before planning remediation efforts.

Own by application and infrastructure teams.
Verify deployment reachability and criticality first.
Plan remediation based on validated risk.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Flyto2 Core?

Flyto2 Core acts as an execution kernel designed to power automation and AI-agent workflows. It functions as a foundational library that developers integrate into systems to handle complex tasks, such as managing automated workflows and processing data pipelines. Because it is a backend engine, it does not typically act as a standalone public service but rather as a component providing essential logic to a larger software application.

What does CVE-2026-67429 mean?

This vulnerability is an improper limitation of a pathname, known as Path Traversal (CWE-22) and External Control of File Name (CWE-73). In plain English, the software fails to properly check where it saves files. Because it ignores safety rules that should keep file operations within a restricted sandbox directory, an attacker can trick the system into saving malicious data into unintended locations on the server's hard drive.

How does an attacker trigger this vulnerability?

An attacker triggers this by interacting with the software's file-handling functions, specifically the image download module. By providing a crafted file path instead of a standard name, they bypass the intended safety checks. This bug occurs only when the application allows caller-controlled input to reach these vulnerable modules; it does not trigger if the application strictly enforces internal environment configurations or hardcoded paths that ignore user input.

Is my system at risk according to Halo Surface Signal?

Halo Surface Signal notes that while Flyto2 Core is a backend component, your risk depends on whether your specific implementation exposes these workflows to the internet. Since this is an automation engine, it is often tucked behind other services. If your custom application takes untrusted inputs and passes them directly into these workflows, the risk increases compared to a deployment where inputs are strictly sanitized or kept internal.

How do I start addressing this issue?

The immediate priority is to locate all systems running versions of Flyto2 Core earlier than 2.26.6. Once identified, map which applications utilize these kernels and determine if they are exposed to external input. After confirming your inventory and identifying the teams responsible for those applications, plan to update to version 2.26.6, which introduces the necessary path validation and sandbox confinement to block arbitrary file writes.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.