CVE-2026-77394

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Source
https://cve.org/CVERecord?id=CVE-2026-77394
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77394.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-77394
Aliases
Published
2026-09-23T18:53:20Z
Modified
2026-09-24T03:46:39Z
Severity
  • 7.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N CVSS Calculator
Summary
OpenC3 COSMOS: Stored, cross-user XSS via Telemetry screen BUTTON widget
Details

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.

Database specific 
{
    "cna_assigner":  "GitHub_M",
    "cwe_ids":  [
        "CWE-79"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77394.json"
}
References

Affected packages

Git / github.com/openc3/cosmos

Affected ranges

Type
GIT
Repo
https://github.com/openc3/cosmos
Events
Introduced
3119c098095481df5a6d24625ccf2f619e283f8c
Fixed
92f8c99cc8ed704d2cf747832f09b72d64b6fa65
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "5.0.6"
        },
        {
            "fixed":  "7.3.0"
        }
    ],
    "source":  "AFFECTED_FIELD"
}

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77394.json"