CVE-2026-109391
Square Squash hasta el commit e73f280 contiene una vulnerabilidad de deserialización insegura que permite a atacantes no autenticados almacenar YAML manipulado a través del endpoint POST /api/1.0/symbolication. Cuando se simbolizan ocurrencias que hacen referencia al UUID de simbolización controlado por el atacante, los valores almacenados se pasan a YAML.load con SafeYAML en modo inseguro, lo que permite la deserialización arbitraria de objetos Ruby y la potencial ejecución de código.
Traducción automática del texto original de NVD (en inglés).
CVSS
- Puntuación base
- 9.2
- Versión
- 4.0
- Vector
- CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/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
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días
- 0.48 %
- Percentil entre todas las CVEs puntuadas
- 40
- Fecha de la puntuación
- 21/10/2026
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
T1059Command and Scripting Interpreterexecution90 % - Impacto secundario
T1565Data Manipulationimpact75 %
CVE-2026-109391: deserialization insegura en endpoint POST sin autenticación (AV:N/PR:N) permite almacenar objetos YAML maliciosos que se deserializan sin validación (CWE-502), resultando en ejecución arbitraria de código Ruby mediante unsafe YAML.load.
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-502
Referencias
Mostrar las 7 referencias
- https://github.com/SquareSquash/web
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb
- https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/lib/workers/symbolication_creator.rb
- https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg
- https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-109391",
"cveTags": [
{
"tags": [
"unsupported-when-assigned"
],
"sourceIdentifier": "disclosure@vulncheck.com"
}
],
"metrics": {
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"options": [
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},
{
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},
{
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}
],
"version": "2.0.3",
"timestamp": "2026-10-13T16:40:50.798651Z"
}
}
],
"cvssMetricV31": [
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"cvssData": {
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"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "HIGH",
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"confidentialityImpact": "HIGH"
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}
],
"cvssMetricV40": [
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"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 9.2,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/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": "HIGH",
"attackRequirements": "PRESENT",
"privilegesRequired": "NONE",
"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "HIGH",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "HIGH",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "NONE",
"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"
}
}
]
},
"affected": [
{
"source": "disclosure@vulncheck.com",
"affectedData": [
{
"repo": "https://github.com/SquareSquash/web",
"vendor": "Square",
"product": "Squash",
"versions": [
{
"status": "affected",
"version": "0",
"versionType": "git",
"lessThanOrEqual": "e73f2805f9eb30780a5c213b001f0f4255660fbf"
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"packageURL": "pkg:github/SquareSquash/web",
"defaultStatus": "unaffected"
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],
"published": "2026-10-12T16:17:04.373",
"references": [
{
"url": "https://github.com/SquareSquash/web",
"source": "disclosure@vulncheck.com"
},
{
"url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/controllers/api/v1_controller.rb",
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"url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/app/models/symbolication.rb",
"source": "disclosure@vulncheck.com"
},
{
"url": "https://github.com/SquareSquash/web/blob/e73f2805f9eb30780a5c213b001f0f4255660fbf/config/preinitializers/safe_yaml.rb",
"source": "disclosure@vulncheck.com"
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{
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"source": "disclosure@vulncheck.com"
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{
"url": "https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/HJ87QX5ifg",
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},
{
"url": "https://www.vulncheck.com/advisories/square-squash-through-commit-e73f280-unauthenticated-yaml-deserialization-via-symbolication-api",
"source": "disclosure@vulncheck.com"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
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"type": "Secondary",
"source": "disclosure@vulncheck.com",
"description": [
{
"lang": "en",
"value": "CWE-502"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "Square Squash through commit e73f280 contains an insecure deserialization vulnerability that allows unauthenticated attackers to store crafted YAML via the POST /api/1.0/symbolication endpoint. When occurrences referencing the attacker-controlled symbolication UUID are symbolicated, the stored values are passed to YAML.load with SafeYAML in unsafe mode, enabling arbitrary Ruby object deserialization and potential code execution."
}
],
"lastModified": "2026-10-16T18:25:45.343",
"sourceIdentifier": "disclosure@vulncheck.com"
}