CVE-2026-42085

MEDIUM

OpenC3 COSMOS: Arbitrary write to plugins directory via path-traversed config filenames

Title source: cna
STIX 2.1

Description

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 save_tool_config() 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.

Scores

CVSS v3 4.3
EPSS 0.0004
EPSS Percentile 11.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-23
Status published
Products (3)
OpenC3/cosmos < 6.10.5
OpenC3/cosmos >= 7.0.0.pre.rc1, < 7.0.0-rc3
rubygems/openc3 0 - 6.10.5RubyGems
Published May 04, 2026
Tracked Since May 04, 2026