{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.12",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.13",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.14",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.15",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.16",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.17",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.18",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.19",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.20",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.21",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.22",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.23",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "Alpine:v3.24",
        "name": "docker",
        "purl": "pkg:apk/alpine/docker?arch=source"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "20.0.0"
            },
            {
              "fixed": "20.10.3-r0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "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/\u003cremapping\u003e\" that cause writing files with extended privileges. Versions 20.10.3 and 19.03.15 contain patches that prevent privilege escalation from remapped user.",
  "id": "ALPINE-CVE-2021-21284",
  "modified": "2026-11-03T06:17:57.979461575Z",
  "published": "2021-02-02T18:15:11.827Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security.alpinelinux.org/vuln/CVE-2021-21284"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2021-21284"
  ]
}