External risk intelligence

OpenC3 COSMOS Command Injection Vulnerability

CVE advisorySeverity: CRITICAL (CVSS 9.9)

CVE-2026-77602

OpenC3 COSMOS is a specialized platform for command and control of embedded systems. While it provides web-based interfaces and APIs that may be network-reachable, these systems are typically deployed within restricted operational, engineering, or laboratory network environments rather than being exposed directly to the public internet in common deployment patterns.

Code Injection

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 affects the OpenC3 COSMOS platform, which is used for managing embedded systems. It allows authenticated users to execute code with higher privileges than intended, potentially leading to unauthorized access to sensitive data and credentials. The main concern is confirming relevance and exposure within your specific deployment.

Allows unauthorized code execution.
Impacts systems managing embedded devices.
Confirm relevance and potential exposure.

Attack Path

How an attacker could exploit the issue

An authenticated user with non-administrator privileges can upload crafted files to specific locations within OpenC3 COSMOS. When these files are later processed by configuration paths, they can lead to arbitrary code execution, potentially granting the attacker access to internal credentials and data. This occurs because certain configuration and scripting features improperly handle user-supplied content, allowing it to be rendered or evaluated with elevated privileges.

Authenticated non-administrator access required.
Triggered by file uploads and configuration reloads.
Risk of credential access and data compromise.

Live Threat

Current exploitation, exposure, and threat context

An authenticated non-administrator user could execute arbitrary code on the system. This could lead to the compromise of internal credentials and sensitive data when supported by the advisory's described conditions, which involve writing content to specific directories and triggering configuration paths that process user-supplied data.

System credentials and data.
Arbitrary code execution.
Unauthorized access and data exposure.

Operational Fix

Recommended remediation, mitigation, and detection steps

Given that OpenC3 COSMOS is used for command and control of embedded systems, platform or infrastructure teams are likely responsible for its operation. The immediate first step is to identify all instances of OpenC3 COSMOS within the environment, confirm their network exposure and criticality, and locate the accountable system owner to prioritize and plan remediation efforts.

Platform/infrastructure teams own the issue.
Verify COSMOS instances and their exposure.
Plan risk-based remediation or vendor coordination.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

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Frequently asked questions

What is OpenC3 COSMOS?

OpenC3 COSMOS is a specialized software platform designed to manage embedded systems. Engineers and operators use it to send command sequences to hardware and receive telemetry data. It acts as the central interface for monitoring and controlling devices in laboratory, aerospace, or industrial operational environments.

What does this CVE-2026-77602 vulnerability mean?

This is a code injection vulnerability (CWE-94). It means the software incorrectly handles user-supplied content by treating it as executable commands. In CVE-2026-77602, non-administrator users can place files that the system later evaluates as Ruby, Python, or ERB code, granting them execution privileges beyond their intended access level.

How is this vulnerability triggered?

An attacker must first authenticate as a non-administrator and upload content into specific directories like 'targets_modified/'. The vulnerability is triggered when the system performs routine operations, such as reloading configurations, processing telemetry definitions, or running suite analysis, which then inadvertently executes the malicious content.

Is my OpenC3 COSMOS instance at risk?

Per Halo Surface Signal, risk depends on your network design. While the software provides web-based interfaces that can be network-reachable, it is typically deployed in restricted operational or engineering environments. If your instance is isolated from public internet access, the window for remote exploitation is significantly lower than for publicly exposed systems.

How should I respond to this vulnerability?

First, identify all deployed OpenC3 COSMOS instances and verify their current version. If you are running any version from 5.1.0 up to, but not including, 7.3.0, you are affected. Coordinate with your infrastructure team to update to version 7.3.0 or later, which contains the fix for this issue.

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.