CVE-2026-77394
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
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N
- Puntuación base: 7.6
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.39%
- Percentil entre todas las CVEs puntuadas: 31
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1189Drive-by Compromiseinitial access85 % - Impacto principal
T1059.007JavaScriptexecution90 % - Impacto secundario
T1005Data from Local Systemcollection80 % - Impacto secundario
T1078.004Cloud Accountsstealth · persistence · privilege escalation · initial access85 %
XSS en widget BUTTON almacenado ejecuta scripts en navegador de otra sesión (T1189). Roba tokens OAuth (T1078.004) y accede localStorage (T1005) con privilegios víctima. AV:N, UI:R confirma interacción del usuario.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-79
Referencias
- https://github.com/OpenC3/cosmos/commit/10371f8f410b9ad588f98dfa3befaaacb6587cd3
- https://github.com/OpenC3/cosmos/pull/3560
- https://github.com/OpenC3/cosmos/releases/tag/v7.3.0
- https://github.com/OpenC3/cosmos/security/advisories/GHSA-gvf2-2rh5-mpgf
- https://github.com/OpenC3/cosmos/security/advisories/GHSA-gvf2-2rh5-mpgf
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-77394",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-77394",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-23T19:27:36.468261Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 7.6,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:L/A:N",
"integrityImpact": "LOW",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "LOW",
"confidentialityImpact": "HIGH"
},
"impactScore": 4.7,
"exploitabilityScore": 2.3
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "OpenC3",
"product": "cosmos",
"versions": [
{
"status": "affected",
"version": ">= 5.0.6, < 7.3.0"
}
]
}
]
}
],
"published": "2026-09-23T19:19:15.343",
"references": [
{
"url": "https://github.com/OpenC3/cosmos/commit/10371f8f410b9ad588f98dfa3befaaacb6587cd3",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/OpenC3/cosmos/pull/3560",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/OpenC3/cosmos/releases/tag/v7.3.0",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/OpenC3/cosmos/security/advisories/GHSA-gvf2-2rh5-mpgf",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/OpenC3/cosmos/security/advisories/GHSA-gvf2-2rh5-mpgf",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-79"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"lastModified": "2026-09-23T20:17:15.660",
"sourceIdentifier": "security-advisories@github.com"
}