CVE-2026-40166
authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, authenticated non-admin users with at least one OAuth2 access token can retrieve the client_secret of confidential OAuth2 providers they have previously authenticated against, exposing sensitive information to users without the correct permissions. This logic is GET /api/v3/oauth2/access_tokens/. The API response includes a nested provider object containing client_id and client_secret for providers configured with client_type: confidential, which should not be accessible to low-privilege users. This issue has been fixed in versions 2025.12.5 and 2026.2.3.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/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: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.56%
- Percentil entre todas las CVEs puntuadas: 45
- 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
T1210Exploitation of Remote Serviceslateral movement70 % - Impacto principal
T1005Data from Local Systemcollection85 % - Impacto secundario
T1078Valid Accountsstealth · persistence · privilege escalation · initial access75 %
Acceso remoto autenticado (PR:L) a API expuesta que revela secretos OAuth2. CWE-200 (exposición de información) en endpoint GET /api/v3/oauth2/access_tokens/. Usuario privilegiado bajo accede a credenciales de proveedores confidenciales sin autorización.
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-200, CWE-863
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-40166",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-40166",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-05-26T18:47:45.180359Z"
}
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
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"baseScore": 7.1,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:N/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": "NONE",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
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"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "NONE",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "LOW",
"vulnConfidentialityImpact": "HIGH",
"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"
}
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"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "goauthentik",
"product": "authentik",
"versions": [
{
"status": "affected",
"version": "< 2025.12.5"
},
{
"status": "affected",
"version": ">= 2026.2.0-rc1, < 2026.2.3"
}
]
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],
"published": "2026-05-22T19:17:03.763",
"references": [
{
"url": "https://github.com/goauthentik/authentik/releases/tag/version%2F2025.12.5",
"source": "security-advisories@github.com"
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{
"url": "https://github.com/goauthentik/authentik/releases/tag/version%2F2026.2.3",
"source": "security-advisories@github.com"
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{
"url": "https://github.com/goauthentik/authentik/security/advisories/GHSA-hhpc-rqgm-pxj4",
"source": "security-advisories@github.com"
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],
"vulnStatus": "Deferred",
"weaknesses": [
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"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
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"lang": "en",
"value": "CWE-200"
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{
"lang": "en",
"value": "CWE-863"
}
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}
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"descriptions": [
{
"lang": "en",
"value": "authentik is an open-source identity provider. In versions prior to 2025.12.5 and 2026.2.0-rc1 through 2026.2.2, authenticated non-admin users with at least one OAuth2 access token can retrieve the client_secret of confidential OAuth2 providers they have previously authenticated against, exposing sensitive information to users without the correct permissions. This logic is GET /api/v3/oauth2/access_tokens/. The API response includes a nested provider object containing client_id and client_secret for providers configured with client_type: confidential, which should not be accessible to low-privilege users. This issue has been fixed in versions 2025.12.5 and 2026.2.3."
},
{
"lang": "es",
"value": "authentik es un proveedor de identidad de código abierto. En versiones anteriores a 2025.12.5 y 2026.2.0-rc1 hasta 2026.2.2, los usuarios autenticados no administradores con al menos un token de acceso OAuth2 pueden recuperar el client_secret de proveedores OAuth2 confidenciales contra los que se han autenticado previamente, exponiendo información sensible a usuarios sin los permisos correctos. Esta lógica es GET /API/v3/oauth2/access_tokens/. La respuesta de la API incluye un objeto de proveedor anidado que contiene client_id y client_secret para proveedores configurados con client_type: confidential, lo cual no debería ser accesible para usuarios con bajos privilegios. Este problema ha sido solucionado en las versiones 2025.12.5 y 2026.2.3."
}
],
"lastModified": "2026-07-23T16:10:00.137",
"sourceIdentifier": "security-advisories@github.com"
}