CVE-2026-85731
oras-go is a Go library for managing OCI artifacts. Prior to 2.6.2, content/file.Store extraction of OCI layers marked with io.deis.oras.content.unpack=true can write outside the store working directory. The pushDir path through extractTarDirectory and ensureLinkPath validates symlink targets lexically, resolveRelToBase skips its parent-symlink walk for root-level entries, and writeFile follows a terminal symlink when opening a regular file.
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A malicious archive can therefore create a symlink chain whose lexical target remains inside the extraction root but whose resolved target is an attacker-selected absolute path, then overwrite that target with a same-named regular-file entry even when AllowPathTraversalOnWrite is false. Pulling an attacker-controlled artifact can create or overwrite any file writable by the process and may lead to code execution. This issue is fixed in version 2.6.2.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Puntuación base: 8.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.68%
- Percentil entre todas las CVEs puntuadas: 51
- 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
T1203Exploitation for Client Executionexecution80 % - Impacto principal
T1565.001Stored Data Manipulationimpact85 % - Impacto secundario
T1059.007JavaScriptexecution70 %
CVE-2026-85731 requiere interacción del usuario (UI:R) para descargar un artefacto OCI malicioso. La cadena de symlinks permite sobrescribir archivos arbitrarios y potencialmente ejecutar código, afectando integridad y disponibilidad del sistema (I:H, A:H).
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-22, CWE-59
Referencias
- https://github.com/oras-project/oras-go/commit/adab2f25ea95ef4e6e41f50db9266a6701399422
- https://github.com/oras-project/oras-go/releases/tag/v2.6.2
- https://github.com/oras-project/oras-go/security/advisories/GHSA-m37j-52j7-pjw7
- https://github.com/oras-project/oras-go/security/advisories/GHSA-m37j-52j7-pjw7
JSON original (NVD)
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{
"id": "CVE-2026-85731",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-85731",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "poc"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"version": "2.0.3",
"timestamp": "2026-09-16T17:24:00.719255Z"
}
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "UNCHANGED",
"version": "3.1",
"baseScore": 8.8,
"attackVector": "NETWORK",
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"integrityImpact": "HIGH",
"userInteraction": "REQUIRED",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "NONE",
"confidentialityImpact": "HIGH"
},
"impactScore": 5.9,
"exploitabilityScore": 2.8
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "oras-project",
"product": "oras-go",
"versions": [
{
"status": "affected",
"version": "< 2.6.2"
}
]
}
]
}
],
"published": "2026-09-16T17:18:15.833",
"references": [
{
"url": "https://github.com/oras-project/oras-go/commit/adab2f25ea95ef4e6e41f50db9266a6701399422",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/oras-project/oras-go/releases/tag/v2.6.2",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/oras-project/oras-go/security/advisories/GHSA-m37j-52j7-pjw7",
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/oras-project/oras-go/security/advisories/GHSA-m37j-52j7-pjw7",
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
}
],
"vulnStatus": "Deferred",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-22"
},
{
"lang": "en",
"value": "CWE-59"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "oras-go is a Go library for managing OCI artifacts. Prior to 2.6.2, content/file.Store extraction of OCI layers marked with io.deis.oras.content.unpack=true can write outside the store working directory. The pushDir path through extractTarDirectory and ensureLinkPath validates symlink targets lexically, resolveRelToBase skips its parent-symlink walk for root-level entries, and writeFile follows a terminal symlink when opening a regular file. A malicious archive can therefore create a symlink chain whose lexical target remains inside the extraction root but whose resolved target is an attacker-selected absolute path, then overwrite that target with a same-named regular-file entry even when AllowPathTraversalOnWrite is false. Pulling an attacker-controlled artifact can create or overwrite any file writable by the process and may lead to code execution. This issue is fixed in version 2.6.2."
}
],
"lastModified": "2026-09-16T18:17:17.963",
"sourceIdentifier": "security-advisories@github.com"
}