CVE-2026-42086 MEDIUM

CVE-2026-42086: OpenC3 COSMOS: Self-XSS in the Command Sender

Vendor Openc3
Product cosmos
Weakness CWE-79 · XSS
Published May 4, 2026
Last update May 4, 2026

CVSS base score

4.6/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 4, 2026 CVE published
May 4, 2026 Record updated