OpenC3 COSMOS provides the functionality needed to send commands to and receive data from one or more embedded systems. From 5.0.6 until 7.3.0, an authenticated actor with system_set permission can store a shared screen through POST /openc3-api/screen whose BUTTON widget action is evaluated by openc3-cosmos-init/plugins/packages/openc3-vue-common/src/widgets/ButtonWidget.vue in another operator's browser session when the button is activated. The stored script runs in the COSMOS origin and can read localStorage.openc3Token, allowing theft of the victim's bearer token, account takeover, and actions with the victim's privileges. The permissive content security policy contributes to execution but is not the primary root cause. This issue is fixed in version 7.3.0.

Project Subscriptions

Vendors Products
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-gvf2-2rh5-mpgf OpenC3 COSMOS: Stored, cross-user XSS via Telemetry screen BUTTON widget
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 23 Sep 2026 21:15:00 +0000

Type Values Removed Values Added
First Time appeared Openc3
Openc3 cosmos
Vendors & Products Openc3
Openc3 cosmos

Wed, 23 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Wed, 23 Sep 2026 19:00:00 +0000

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. From 5.0.6 until 7.3.0, an authenticated actor with system_set permission can store a shared screen through POST /openc3-api/screen whose BUTTON widget action is evaluated by openc3-cosmos-init/plugins/packages/openc3-vue-common/src/widgets/ButtonWidget.vue in another operator's browser session when the button is activated. The stored script runs in the COSMOS origin and can read localStorage.openc3Token, allowing theft of the victim's bearer token, account takeover, and actions with the victim's privileges. The permissive content security policy contributes to execution but is not the primary root cause. This issue is fixed in version 7.3.0.
Title OpenC3 COSMOS: Stored, cross-user XSS via Telemetry screen BUTTON widget
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 7.6, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-23T19:28:31.603Z

Reserved: 2026-08-20T19:55:27.022Z

Link: CVE-2026-77394

cve-icon Vulnrichment

Updated: 2026-09-23T19:28:25.805Z

cve-icon NVD

Status : Deferred

Published: 2026-09-23T19:19:15.343

Modified: 2026-09-23T20:17:15.660

Link: CVE-2026-77394

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-23T21:00:13Z

Weaknesses