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GHSA-4jvx-93h3-f45h

MEDIUMFix: OpenC3/cosmos@9957a9f

GHSA-4jvx-93h3-f45h is a medium-severity (CVSS 4.3) vulnerability in openc3. O3 Security confirms whether GHSA-4jvx-93h3-f45h is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

OpenC3 COSMOS allows arbitrary writes to plugins directory via path-traversed config filenames

Also known asCVE-2026-42085PYSEC-2026-2243
Published
Apr 22, 2026
Updated
Jul 13, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed

Real-World Exposure

2 pkgs affected
💎openc3💎openc3

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Summary

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.

Details

In function save_tool_config() (local_mode.rb) responsible for saving user-supplied tool configuration, the desired saving directory is not sufficiently enforced, instead allowing writes inside entire OPENC3_LOCAL_MODE_PATH.

PoC

  1. Navigate to any tool that enables “Save Configuration” option in left-hand drop-down menu (here Limits Monitor as an example)
  2. Save a new config with path traversal name using “../” sequences to escape desired directory (up to 3 levels high)
  3. Observe new files created in /plugins directory by inspecting docker container directly (openc3-COSMOS-cmd-tlm-api) or using Bucket Explorer (plugin_default)
<img width="811" height="584" alt="image" src="https://github.com/user-attachments/assets/015a59b4-8b18-4801-aef0-df4831d5c1c3" /> <img width="720" height="664" alt="image" src="https://github.com/user-attachments/assets/8ca4a5b7-ee45-4c3b-99f6-f41f974a74a7" />

Impact

Modifying the data of other plugins

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
💎RubyGemsopenc3all versions6.10.5
💎RubyGemsopenc37.0.0.pre.rc1&&< 7.0.0-rc37.0.0-rc3

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openc3. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update openc3 to 6.10.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-4jvx-93h3-f45h is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-4jvx-93h3-f45h is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-4jvx-93h3-f45h. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Summary 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. ### Details In function `save_tool_config(
O3 Security · Impact-Aware SCA

Is GHSA-4jvx-93h3-f45h in your dependencies?

O3 detects GHSA-4jvx-93h3-f45h across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.