CVE-2021-21284
Estado: ModificadaMedia (6.8)—
In Docker before versions 9.03.15, 20.10.3 there is a vulnerability involving the --userns-remap option in which access to remapped root allows privilege escalation to real root. When using "--userns-remap", if the root user in the remapped namespace has access to the host filesystem they can modify files under "/var/lib/docker/<remapping>" that cause writing files with extended privileges. Versions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user.
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N
- Puntuación base: 6.8
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 1.06%
- Percentil entre todas las CVEs puntuadas: 64
- 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).
Tecnologías afectadas (3)
CWE
- CWE-22
- CWE-22
Referencias
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
- https://security.gentoo.org/glsa/202107-23
- https://security.netapp.com/advisory/ntap-20210226-0005/
- https://www.debian.org/security/2021/dsa-4865
- https://docs.docker.com/engine/release-notes/#20103
- https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c
- https://github.com/moby/moby/releases/tag/v19.03.15
- https://github.com/moby/moby/releases/tag/v20.10.3
- https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc
- https://security.gentoo.org/glsa/202107-23
- https://security.netapp.com/advisory/ntap-20210226-0005/
- https://www.debian.org/security/2021/dsa-4865
JSON original (NVD)
Mostrar
{
"id": "CVE-2021-21284",
"cveTags": [],
"metrics": {
"cvssMetricV2": [
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"version": "2.0",
"baseScore": 2.7,
"accessVector": "ADJACENT_NETWORK",
"vectorString": "AV:A/AC:L/Au:S/C:N/I:P/A:N",
"authentication": "SINGLE",
"integrityImpact": "PARTIAL",
"accessComplexity": "LOW",
"availabilityImpact": "NONE",
"confidentialityImpact": "NONE"
},
"acInsufInfo": false,
"impactScore": 2.9,
"baseSeverity": "LOW",
"obtainAllPrivilege": false,
"exploitabilityScore": 5.1,
"obtainUserPrivilege": false,
"obtainOtherPrivilege": false,
"userInteractionRequired": false
}
],
"cvssMetricV31": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 6.8,
"attackVector": "ADJACENT_NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "LOW",
"confidentialityImpact": "NONE"
},
"impactScore": 4,
"exploitabilityScore": 2.3
},
{
"type": "Primary",
"source": "nvd@nist.gov",
"cvssData": {
"scope": "CHANGED",
"version": "3.1",
"baseScore": 6.8,
"attackVector": "ADJACENT_NETWORK",
"baseSeverity": "MEDIUM",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
"integrityImpact": "HIGH",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "NONE",
"privilegesRequired": "LOW",
"confidentialityImpact": "NONE"
},
"impactScore": 4,
"exploitabilityScore": 2.3
}
]
},
"affected": [
{
"source": "security-advisories@github.com",
"affectedData": [
{
"vendor": "moby",
"product": "moby",
"versions": [
{
"status": "affected",
"version": "< 19.03.15"
},
{
"status": "affected",
"version": ">= 20.0.0, < 20.10.3"
}
]
}
]
}
],
"published": "2021-02-02T18:15:11.827",
"references": [
{
"url": "https://docs.docker.com/engine/release-notes/#20103",
"tags": [
"Release Notes",
"Vendor Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/moby/moby/releases/tag/v19.03.15",
"tags": [
"Release Notes",
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/moby/moby/releases/tag/v20.10.3",
"tags": [
"Release Notes",
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc",
"tags": [
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://security.gentoo.org/glsa/202107-23",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://security.netapp.com/advisory/ntap-20210226-0005/",
"tags": [
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://www.debian.org/security/2021/dsa-4865",
"tags": [
"Third Party Advisory"
],
"source": "security-advisories@github.com"
},
{
"url": "https://docs.docker.com/engine/release-notes/#20103",
"tags": [
"Release Notes",
"Vendor Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://github.com/moby/moby/commit/64bd4485b3a66a597c02c95f5776395e540b2c7c",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://github.com/moby/moby/releases/tag/v19.03.15",
"tags": [
"Release Notes",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://github.com/moby/moby/releases/tag/v20.10.3",
"tags": [
"Release Notes",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://github.com/moby/moby/security/advisories/GHSA-7452-xqpj-6rpc",
"tags": [
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://security.gentoo.org/glsa/202107-23",
"tags": [
"Patch",
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://security.netapp.com/advisory/ntap-20210226-0005/",
"tags": [
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
},
{
"url": "https://www.debian.org/security/2021/dsa-4865",
"tags": [
"Third Party Advisory"
],
"source": "af854a3a-2127-422b-91ae-364da2661108"
}
],
"vulnStatus": "Modified",
"weaknesses": [
{
"type": "Secondary",
"source": "security-advisories@github.com",
"description": [
{
"lang": "en",
"value": "CWE-22"
}
]
},
{
"type": "Primary",
"source": "nvd@nist.gov",
"description": [
{
"lang": "en",
"value": "CWE-22"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In Docker before versions 9.03.15, 20.10.3 there is a vulnerability involving the --userns-remap option in which access to remapped root allows privilege escalation to real root. When using \"--userns-remap\", if the root user in the remapped namespace has access to the host filesystem they can modify files under \"/var/lib/docker/<remapping>\" that cause writing files with extended privileges. Versions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user."
},
{
"lang": "es",
"value": "En Docker versiones anteriores a 9.03.15, 20.10.3, se presenta una vulnerabilidad que involucra la opción --userns-remap en la que un acceso a una root reasignada permite una escalada de privilegios a la root actual. Cuando se usa \"--userns-remap\", si el usuario root en el espacio de nombres reasignado tiene acceso al sistema de archivos del host, puede modificar archivos en \"/var/lib/docker/(remapping)\" que causa la escritura de archivos con privilegios extendidos. Las versiones 20.10.3 y 19.03.15 contienen parches que evitan una escalada de privilegios del usuario reasignado"
}
],
"lastModified": "2026-06-17T03:35:11.603",
"configurations": [
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:docker:docker:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "C6B22016-AB78-4E82-9F65-AEC2526F3EDF",
"versionEndExcluding": "19.03.15"
},
{
"criteria": "cpe:2.3:a:docker:docker:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "B4427D14-D219-490B-8467-40FE253775A1",
"versionEndExcluding": "20.10.3",
"versionStartIncluding": "20.0.0"
}
],
"operator": "OR"
}
]
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"
}
],
"operator": "OR"
}
]
},
{
"nodes": [
{
"negate": false,
"cpeMatch": [
{
"criteria": "cpe:2.3:a:netapp:e-series_santricity_os_controller:*:*:*:*:*:*:*:*",
"vulnerable": true,
"matchCriteriaId": "BD1E9594-C46F-40D1-8BC2-6B16635B55C4",
"versionEndIncluding": "11.60.3",
"versionStartIncluding": "11.0.0"
}
],
"operator": "OR"
}
]
}
],
"sourceIdentifier": "security-advisories@github.com"
}