# CVE-2026-77602: OpenC3 COSMOS: Authenticated remote code execution via the user-writable config overlay (table definitions, cmd/tlm definitions, and script suites)

> Authenticated non-admin users can achieve remote code execution and privilege escalation by injecting malicious content into user-writable configuration overlays.

- **Severity:** Critical 9.9 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Sep 2026
- **Updated:** 29 Sep 2026
- **Also known as:** GHSA-jjq7-m736-w977

## What is CVE-2026-77602?

CVE-2026-77602 is a critical code injection vulnerability in OpenC3 cosmos, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

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.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-77602?

2 open source packages ship an affected version, including openc3.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `openc3` | RubyGems | From 5.1.0 | 7.3.0 |
| `openc3` | RubyGems | From 5.1.0 | 7.3.0 |

## How do I fix CVE-2026-77602?

Upgrade openc3 to 7.3.0 or later.

## Is CVE-2026-77602 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77602 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-77602 and fix it if it is affected.

What it is: CVE-2026-77602 is a critical code injection vulnerability in OpenC3 cosmos, published on 23 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77602 exists.

Affected packages and fixed versions:
- openc3 (RubyGems): affected from 5.1.0; fixed in 7.3.0
- openc3 (RubyGems): affected from 5.1.0; fixed in 7.3.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-77602/ (Markdown: https://insights.sbomify.com/CVE-2026-77602/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-77602
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-77602
- OSV: https://osv.dev/vulnerability/CVE-2026-77602

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-77602/
Summaries are generated and may contain mistakes; the official description above is the record.