CVE-2026-77394
CVE-2026-77394 · OpenC3 COSMOS: Stored, cross-user XSS via Telemetry screen BUTTON widget
This page contains facts from public vulnerability sources. Check the original advisory before updating.
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.
CVSS 7.6 · High · EPSS 0.4% · Public exploit · Fix available
- Published
- Updated
Stack: node
Affected products and versions
cosmos
- Versions
- >= 5.0.6, < 7.3.0: Affected
No fix published
@openc3/vue-common npm
- Affected ranges
- SEMVER: ≥ 5.0.6, < 7.3.0
Update to 7.3.0