CVE-2026-42086

OpenC3 COSMOS: Self-XSS in the Command Sender

Published May 4, 2026 CVSS 3.1 · 4.6 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-ffq5-qpvf-xq7x OpenC3 COSMOS is Vulnerable to Self-XSS Through the Command Sender
History
Type Values Removed Values Added
CPEs cpe:2.3:a:openc3:cosmos:*:*:*:*:open_source:*:*:*
cpe:2.3:a:openc3:cosmos:7.0.0:rc1:*:*:open_source:*:*:*
cpe:2.3:a:openc3:cosmos:7.0.0:rc2:*:*:open_source:*:*:*
cpe:2.3:a:openc3:cosmos:7.0.0:rc3:*:*:open_source:*:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Openc3
Openc3 cosmos
Vendors & Products Openc3
Openc3 cosmos
Type Values Removed Values Added
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.
Title OpenC3 COSMOS: Self-XSS in the Command Sender
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 4.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
May 4, 2026, 7:47 PM
Reserved
Apr 23, 2026, 7:17 PM
Status
Analyzed
Published
May 4, 2026, 6:16 PM
Modified
Oct 26, 2026, 7:10 PM