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.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
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
Which versions are affected by CVE-2026-77602?
2 open source packages ship an affected version, including openc3.
| Package | 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.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-77602 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77602 exists.
Sources
Also known as GHSA-jjq7-m736-w977.