CVE-2026-42086
OpenC3 COSMOS is Vulnerable to Self-XSS Through the Command Sender
Description
OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. Prior to version 7.0.0, the Command Sender UI uses an unsafe eval() function on array-like command parameters, which allows a user-supplied payload to execute in the browser when sending a command. This creates a self-XSS risk because an attacker can trigger their own script execution in the victim’s session, if allowed to influence the array parameter input, for example via phishing. If successful, an attacker may read or modify data in the authenticated browser context, including session tokens in local storage. This issue has been patched in version 7.0.0.
How to fix CVE-2026-42086
To remediate CVE-2026-42086, upgrade the affected package to a fixed version below.
- —upgrade to 7.0.0 or later
- —upgrade to 7.0.0 or later
- —upgrade to 7.0.0 or later
Is CVE-2026-42086 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 7.0.0
- from 0, < 7.0.0
- from 0, < 7.0.0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N |