CVE-2026-88899
knowns versions before 0.31.0 fail to properly validate the x-opencode-directory request header in the /api/opencode proxy endpoint. Remote attackers can supply arbitrary directory paths to execute file operations outside the project root on the host system.
CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/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
- Puntuación base: 9.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.81%
- Percentil entre todas las CVEs puntuadas: 55
- 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
T1190Exploit Public-Facing Applicationinitial access95 % - Impacto principal
T1005Data from Local Systemcollection85 % - Impacto secundario
T1027.001Binary Paddingstealth60 % - Impacto secundario
T1565.002Transmitted Data Manipulationimpact75 %
AV:N/PR:N/UI:N indica explotación remota sin privilegios (T1190). La falta de validación del header permite acceso a archivos fuera del directorio raíz (T1005). CWE-73 sugiere manipulación de rutas para lectura y posible escritura de datos (T1565.002).
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-73
Referencias
- https://github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296
- https://github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657
- https://github.com/knowns-dev/knowns/releases/tag/v0.31.0
- https://github.com/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w
- https://www.vulncheck.com/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header
JSON original (NVD)
Mostrar
{
"id": "CVE-2026-88899",
"cveTags": [],
"metrics": {
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{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-88899",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-09-11T17:11:17.124340Z"
}
}
],
"cvssMetricV31": [
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"version": "3.1",
"baseScore": 9.8,
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"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 3.9
}
],
"cvssMetricV40": [
{
"type": "Secondary",
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"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 9.3,
"Automatable": "NOT_DEFINED",
"attackVector": "NETWORK",
"baseSeverity": "CRITICAL",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/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",
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"attackRequirements": "NONE",
"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": [
{
"vendor": "knowns-dev",
"product": "knowns",
"versions": [
{
"status": "affected",
"version": "0",
"lessThan": "0.31.0",
"versionType": "semver"
},
{
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"versionType": "semver"
}
],
"packageURL": "pkg:npm/knowns",
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}
],
"published": "2026-09-10T16:18:12.120",
"references": [
{
"url": "https://github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296",
"source": "disclosure@vulncheck.com"
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{
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},
{
"url": "https://github.com/knowns-dev/knowns/releases/tag/v0.31.0",
"source": "disclosure@vulncheck.com"
},
{
"url": "https://github.com/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w",
"source": "disclosure@vulncheck.com"
},
{
"url": "https://www.vulncheck.com/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header",
"source": "disclosure@vulncheck.com"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "disclosure@vulncheck.com",
"description": [
{
"lang": "en",
"value": "CWE-73"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "knowns versions before 0.31.0 fail to properly validate the x-opencode-directory request header in the /api/opencode proxy endpoint. Remote attackers can supply arbitrary directory paths to execute file operations outside the project root on the host system."
}
],
"lastModified": "2026-09-11T21:17:55.460",
"sourceIdentifier": "disclosure@vulncheck.com"
}