CVE-2026-40591
FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the phone-conversation creation flow accepts attacker-controlled `customer_id`, `name`, `to_email`, and `phone` values and resolves the target customer in the backend without enforcing mailbox-scoped customer visibility. As a result, a low-privileged agent who can create a phone conversation in Mailbox A can bind the new Mailbox A phone conversation to a hidden customer from Mailbox B and add a new alias email to that hidden customer record by supplying `to_email`. Version 1.8.214 fixes the vulnerability.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N
- Puntuación base: 7.1
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.34%
- Percentil entre todas las CVEs puntuadas: 25
- Fecha de la puntuación: 5/10/2026
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 movement75 % - Impacto principal
T1098.002Additional Email Delegate Permissionspersistence · privilege escalation80 % - Impacto secundario
T1552.007Container APIcredential access70 %
Requiere PR:L (acceso remoto con privilegios de agente) y acceso local a clientes ocultos entre mailboxes → T1210. Modifica alias de email de cuenta remota (T1098.002) y expone datos de cliente (T1552.007).
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-639
Referencias
- https://github.com/freescout-help-desk/freescout/commit/83eea1ca47d97c6cdc90c501734bc2579b014a34
- https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp
- https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-40591",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-40591",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-04-21T17:46:34.226416Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 7.1,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "LOW",
"confidentialityImpact": "LOW"
},
"impactScore": 4.2,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "freescout-help-desk",
"product": "freescout",
"versions": [
{
"status": "affected",
"version": "< 1.8.214"
}
]
}
]
}
],
"published": "2026-04-21T17:16:56.940",
"references": [
{
"url": "https://github.com/freescout-help-desk/freescout/commit/83eea1ca47d97c6cdc90c501734bc2579b014a34",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/freescout-help-desk/freescout/releases/tag/1.8.214",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-9ff4-mmhv-x6jp",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-639"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "FreeScout is a free self-hosted help desk and shared mailbox. Prior to version 1.8.214, the phone-conversation creation flow accepts attacker-controlled `customer_id`, `name`, `to_email`, and `phone` values and resolves the target customer in the backend without enforcing mailbox-scoped customer visibility. As a result, a low-privileged agent who can create a phone conversation in Mailbox A can bind the new Mailbox A phone conversation to a hidden customer from Mailbox B and add a new alias email to that hidden customer record by supplying `to_email`. Version 1.8.214 fixes the vulnerability."
}
],
"lastModified": "2026-06-17T10:45:29.997",
"sourceIdentifier": "security-advisories@github.com"
}