CVE-2026-53595
FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the public endpoint `POST /user-setup/{hash}/{invite_sent_at}` (`OpenController@userSetupSave`) selects the target account solely by its `invite_hash` column, then overwrites that account's email and password and logs in as it. No authentication, cookie, or prior session is required. After a user activates, FreeScout sets `invite_hash` to the empty string.
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On MySQL and MariaDB, `VARCHAR` equality ignores trailing spaces, so a single URL-encoded space (`%20`) matches the stored empty string and selects the lowest-id activated user. The expiry guard decrypts `invite_sent_at` with the target's password hash, but `Helper::decrypt` returns its raw input unchanged when decryption fails. A plaintext numeric value such as `9999999999` therefore passes the time-to-live check without any secret. The result is that an anonymous attacker sets the email and password of the lowest-id activated FreeScout account (a support agent, or an administrator if one was added by invitation) and authenticates as that account. Version 1.8.224 contains a fix.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L
- Puntuación base: 9.4
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 1.94%
- Percentil entre todas las CVEs puntuadas: 79
- Fecha de la puntuación: 4/10/2026
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
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1078Valid Accountsstealth · persistence · privilege escalation · initial access95 % - Impacto secundario
T1098.001Additional Cloud Credentialspersistence · privilege escalation90 % - Impacto secundario
T1565.001Stored Data Manipulationimpact85 %
Endpoint público sin autenticación (POST /user-setup) explotable remotamente vía bypass de validación de hash y timestamp. Permite cambiar credenciales y acceso como cuenta existente (impacto: autenticación no autorizada). CWE-287 (autenticación débil), CVSS crítico con C:H/I:H confirma acceso compl
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-178, CWE-287, CWE-640
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-53595",
"cveTags": [],
"metrics": {
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{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"id": "CVE-2026-53595",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-07-21T13:20:35.944303Z"
}
}
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"version": "3.1",
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"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "LOW",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.5,
"exploitabilityScore": 3.9
}
]
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"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "freescout-help-desk",
"product": "freescout",
"versions": [
{
"status": "affected",
"version": "< 1.8.224"
}
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],
"published": "2026-07-20T21:16:48.417",
"references": [
{
"url": "https://github.com/freescout-help-desk/freescout/security/advisories/GHSA-jqj5-r72v-v29g",
"source": "security-advisories@github.com"
},
{
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"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
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"weaknesses": [
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"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-178"
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{
"lang": "en",
"value": "CWE-287"
},
{
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"value": "CWE-640"
}
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}
],
"descriptions": [
{
"lang": "en",
"value": "FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the public endpoint `POST /user-setup/{hash}/{invite_sent_at}` (`OpenController@userSetupSave`) selects the target account solely by its `invite_hash` column, then overwrites that account's email and password and logs in as it. No authentication, cookie, or prior session is required. After a user activates, FreeScout sets `invite_hash` to the empty string. On MySQL and MariaDB, `VARCHAR` equality ignores trailing spaces, so a single URL-encoded space (`%20`) matches the stored empty string and selects the lowest-id activated user. The expiry guard decrypts `invite_sent_at` with the target's password hash, but `Helper::decrypt` returns its raw input unchanged when decryption fails. A plaintext numeric value such as `9999999999` therefore passes the time-to-live check without any secret. The result is that an anonymous attacker sets the email and password of the lowest-id activated FreeScout account (a support agent, or an administrator if one was added by invitation) and authenticates as that account. Version 1.8.224 contains a fix."
}
],
"lastModified": "2026-07-21T19:25:11.717",
"sourceIdentifier": "security-advisories@github.com"
}