CVE-2026-77602 in COSMOS
Summary
by MITRE • 09/23/2026
OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.1.0 until 7.3.0, authenticated non-administrator users can write content under targets_modified/ that is later executed by multiple configuration paths below the intended code-execution privilege tier. Table and command or telemetry definitions are processed through ConfigParser, PacketConfig, GENERIC_READ_CONVERSION, or GENERIC_WRITE_CONVERSION, allowing ERB rendering or Ruby and Python evaluation, while openc3-cosmos-script-runner-api/scripts/run_suite_analysis.rb executes suite procedure files through require. Storage uploads, screen saves, and script creation can place content in the overlay, and triggering table processing, a cmd/tlm reload, or suite analysis executes the content in cmd-tlm-api, decom microservices, or Script Runner with access to internal credentials and data. This issue is fixed in version 7.3.0.
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Analysis
by VulDB Data Team • 09/23/2026
The vulnerability identified within OpenC3 COSMOS versions ranging from 5.1.0 through 7.3.0 represents a critical insecure configuration path that allows authenticated non-administrator users to achieve unauthorized code execution with elevated privileges. This flaw fundamentally undermines the intended privilege separation model of the platform, which is designed to restrict lower-privileged users from modifying core system configurations or executing arbitrary scripts within higher-security contexts. The root cause lies in how the application handles user-uploaded content and configuration overlays. Specifically, authenticated users who do not hold administrator roles are permitted to write files into the targets_modified directory structure. While this functionality is intended for legitimate customization of target definitions by lower-privileged operators, it inadvertently creates a vector for privilege escalation because these modified configurations are subsequently processed by system components that operate with significantly higher authority levels than those of the user who created them.
The technical mechanism enabling this exploitation involves several distinct processing pathways within the OpenC3 architecture. When configuration changes or telemetry definitions are saved via storage uploads, screen saves, or script creation interfaces, the content is placed into an overlay directory. This data is then ingested by various internal services such as ConfigParser, PacketConfig, and specific conversion handlers like GENERIC_READ_CONVERSION and GENERIC_WRITE_CONVERSION. These components utilize ERB templating engines to render configuration files, which inherently support Ruby code execution. Furthermore, certain telemetry definitions allow for the evaluation of embedded Python scripts. Consequently, an attacker can craft malicious configuration payloads containing arbitrary Ruby or Python commands that are executed when these configurations are loaded by higher-privileged backend services. Additionally, the script runner component processes suite procedure files through standard Ruby require statements, providing another avenue for executing code placed in accessible directories with elevated permissions.
The operational impact of this vulnerability is severe due to the context in which the malicious code executes. The compromised components include cmd-tlm-api, decom microservices, and the Script Runner service. These services typically possess access to internal credentials, sensitive telemetry data, and direct control over embedded systems connected to the OpenC3 platform. By exploiting this flaw, an attacker can bypass authentication restrictions and execute commands as if they were a system administrator or even a root-level process within the microservice environment. This allows for complete compromise of the integrity and confidentiality of the operational technology infrastructure managed by COSMOS. The attacker could potentially manipulate real-time data streams, issue unauthorized control commands to physical devices, exfiltrate sensitive configuration details, or establish persistent backdoors within the network segment hosting these services.
This vulnerability aligns with CWE-269 Improper Privilege Management and CWE-78 OS Command Injection via ERB template injection. From a tactical perspective, it maps to MITRE ATT&CK techniques related to privilege escalation and lateral movement through configuration file manipulation. The attack chain typically involves initial access as an authenticated user, followed by abuse of the targets_modified write permission, crafting malicious payload content utilizing Ruby or Python code embedded in configuration files, and finally triggering execution via a reload command or suite analysis routine that processes these files with elevated privileges.
Mitigation for this issue requires immediate upgrading to version 7.3.0 or later, where the developers have addressed the insecure handling of user-modifiable configurations. In environments where an upgrade is not immediately feasible, administrators should enforce strict access controls on the targets_modified directory and associated API endpoints to ensure that only users with explicit administrative privileges can write files in locations processed by high-privilege services. Additionally, implementing input validation and sanitization for all configuration uploads, particularly those involving ERB templates or script definitions, is essential. Network segmentation strategies should also be reviewed to limit the blast radius if a lower-privileged account is compromised, ensuring that microservices with elevated privileges are isolated from general user-facing interfaces wherever possible.