Log in Start free

Vulnerability · Published May 4, 2026 · Assigned by GitHub_M

CVE-2026-42085OpenC3 COSMOS: Arbitrary write to plugins directory via path-traversed config filenames

Medium 4.3

In plain English

A medium-severity security flaw in cosmos from OpenC3. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.3%top 75.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIopenc36.10.5PYSEC-2026-2243
RubyGemsopenc36.10.5GHSA-4jvx-93h3-f45h
RubyGemsopenc37.0.0-rc3GHSA-4jvx-93h3-f45h

Affected products (as reported)

VendorProductVersions
OpenC3 cosmos < 6.10.5>= 7.0.0.pre.rc1, < 7.0.0-rc3

Weakness: CWE-23 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

References