CVE-2026-42085: OpenC3 COSMOS: Arbitrary write to plugins directory via path-traversed config filenames
OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to versions 6.10.5 and 7.0.0-rc3, OpenC3 COSMOS contains a design flaw in the savetoolconfig() function that allows saving tool configuration files at arbitrary locations inside the shared /plugins directory tree by supplying crafted configuration filenames. Although the implementation sufficiently mitigates standard path traversal attacks, by canonicalizing filename to an absolute path, all plugins share this same root directory. That enables users to create arbitrary file structures and overwrite existing configuration files within the shared /plugins directory. This issue has been patched in versions 6.10.5 and 7.0.0-rc3.
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2026-42085?
CVE-2026-42085 is classified as a high severity vulnerability due to the potential for arbitrary file writes.
How do I fix CVE-2026-42085?
To fix CVE-2026-42085, upgrade OpenC3 COSMOS to version 6.10.5 or 7.0.0-rc3 or later.
What types of systems are affected by CVE-2026-42085?
CVE-2026-42085 affects OpenC3 COSMOS versions prior to 6.10.5 and 7.0.0-rc3.
Can CVE-2026-42085 lead to data loss?
Yes, CVE-2026-42085 could potentially lead to data loss through unauthorized file modification.
What does CVE-2026-42085 exploit?
CVE-2026-42085 exploits a design flaw that allows for path traversal in config filenames.