CVE-2026-105090
Formbricks before 5.4.4 and 6 before 6.0.1 allows stored XSS. The survey-level Custom Head Scripts feature did not enforce the documented Manage permission boundary. A workspace member holding only readWrite permission could configure Custom Head Scripts on a survey, an operation the documentation restricts to the Manage role. Because the configured scripts execute in the authenticated browser session of any user who opens the affected survey, a lower-privileged member can run arbitrary JavaScript (stored cross-site scripting) in the session of higher-privileged users. Fixed versions require Manage access to modify survey Custom Head Scripts.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 5.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.26%
- Percentil entre todas las CVEs puntuadas: 17
- 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
T1203Exploitation for Client Executionexecution85 % - Impacto principal
T1059.007JavaScriptexecution90 % - Impacto secundario
T1078Valid Accountsstealth · persistence · privilege escalation · initial access75 %
XSS almacenado en scripts personalizados de encuestas ejecutados en sesión autenticada de usuarios con más privilegios (UI:P + sesión autenticada = T1203). Impacto: ejecución de JavaScript arbitrario (T1059.007) y acceso a sesiones de usuarios privilegiados (T1078).
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-863
Referencias
- https://github.com/formbricks/formbricks/pull/9432
- https://github.com/formbricks/formbricks/releases/tag/5.4.4
- https://github.com/formbricks/formbricks/releases/tag/6.0.1
- https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html
- https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-105090",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-105090",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-10-05T17:04:02.074755Z"
}
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "cve@mitre.org",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 5.1,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "MEDIUM",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "PASSIVE",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "LOW",
"subIntegrityImpact": "LOW",
"vulnIntegrityImpact": "LOW",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "NONE",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "LOW",
"vulnConfidentialityImpact": "LOW",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "cve@mitre.org",
"affectedData": [
{
"vendor": "Formbricks",
"product": "Formbricks",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "5.4.4",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.0.0",
"lessThan": "6.0.1",
"versionType": "semver"
}
],
"collectionURL": "https://github.com/formbricks/formbricks",
"defaultStatus": "unaffected"
}
]
}
],
"published": "2026-10-03T02:17:18.370",
"references": [
{
"url": "https://github.com/formbricks/formbricks/pull/9432",
"source": "cve@mitre.org"
},
{
"url": "https://github.com/formbricks/formbricks/releases/tag/5.4.4",
"source": "cve@mitre.org"
},
{
"url": "https://github.com/formbricks/formbricks/releases/tag/6.0.1",
"source": "cve@mitre.org"
},
{
"url": "https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html",
"source": "cve@mitre.org"
},
{
"url": "https://www.sec4check.pl/blog/posts/cve-formbricks-broken-access-control-stored-xss-custom-head-scripts.html",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"type": "Secondary",
"source": "cve@mitre.org",
"description": [
{
"lang": "en",
"value": "CWE-863"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Formbricks before 5.4.4 and 6 before 6.0.1 allows stored XSS. The survey-level Custom Head Scripts feature did not enforce the documented Manage permission boundary. A workspace member holding only readWrite permission could configure Custom Head Scripts on a survey, an operation the documentation restricts to the Manage role. Because the configured scripts execute in the authenticated browser session of any user who opens the affected survey, a lower-privileged member can run arbitrary JavaScript (stored cross-site scripting) in the session of higher-privileged users. Fixed versions require Manage access to modify survey Custom Head Scripts."
}
],
"lastModified": "2026-10-06T16:08:27.613",
"sourceIdentifier": "cve@mitre.org"
}