{
  "cveId": "CVE-2021-43816",
  "url": "https://patchblox.com/security/cve/CVE-2021-43816",
  "summary": "CVE-2021-43816 is fixed in 2 products on 1 platform, first by containerd 1.5.9-0ubuntu1~18.04.1, released January 5, 2022. It is not reported as exploited. Patch Radar priority: Urgent.",
  "title": "containerd: containerd is an open source container runtime",
  "description": "containerd is an open source container runtime. On installations using SELinux, such as EL8 (CentOS, RHEL), Fedora, or SUSE MicroOS, with containerd since v1.5.0-beta.0 as the backing container runtime interface (CRI), an unprivileged pod scheduled to the node may bind mount, via hostPath volume, any privileged, regular file on disk for complete read/write access (sans delete). Such is achieved by placing the in-container location of the hostPath volume mount at either \u0060/etc/hosts\u0060, \u0060/etc/hostname\u0060, or \u0060/etc/resolv.conf\u0060. These locations are being relabeled indiscriminately to match the container process-label which effectively elevates permissions for savvy containers that would not normally be able to access privileged host files. This issue has been resolved in version 1.5.9. Users are advised to upgrade as soon as possible.",
  "published": "2022-01-05T11:15:00Z",
  "severity": "critical",
  "cvss": 9.1,
  "cvssVector": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
  "epss": 0.01809,
  "epssPercentile": 0.78736,
  "priority": "Urgent",
  "priorityTier": 2,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "1.5.9~ds1-1",
      "fix": "DEBIAN-CVE-2021-43816",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-43816",
      "released": "2022-01-05T19:15:08Z"
    },
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "1.5.9~ds1-1",
      "fix": "DEBIAN-CVE-2021-43816",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-43816",
      "released": "2022-01-05T19:15:08Z"
    },
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Debian 14",
      "fixedVersion": "1.5.9~ds1-1",
      "fix": "DEBIAN-CVE-2021-43816",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-43816",
      "released": "2022-01-05T19:15:08Z"
    },
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.5.9-0ubuntu1~18.04.1",
      "fix": "containerd 1.5.9-0ubuntu1~18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-containerd-1.5.9-0ubuntu1-18.04.1",
      "released": "2022-01-05T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.5.9-0ubuntu1~20.04.4",
      "fix": "containerd 1.5.9-0ubuntu1~20.04.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-containerd-1.5.9-0ubuntu1-20.04.4",
      "released": "2022-03-01T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "containerd",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.5.9-0ubuntu1",
      "fix": "containerd 1.5.9-0ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-containerd-1.5.9-0ubuntu1",
      "released": "2022-01-05T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "golang-github-containerd-containerd-dev",
      "release": "Ubuntu 18.04.6 LTS (bionic)",
      "fixedVersion": "1.5.9-0ubuntu1~18.04.1",
      "fix": "golang-github-containerd-containerd-dev 1.5.9-0ubuntu1~18.04.1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-bionic-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1-18.04.1",
      "released": "2022-01-05T11:15:00Z"
    },
    {
      "platform": "linux",
      "product": "golang-github-containerd-containerd-dev",
      "release": "Ubuntu 20.04 LTS (focal)",
      "fixedVersion": "1.5.9-0ubuntu1~20.04.4",
      "fix": "golang-github-containerd-containerd-dev 1.5.9-0ubuntu1~20.04.4",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-focal-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1-20.04.4",
      "released": "2022-03-01T16:00:00Z"
    },
    {
      "platform": "linux",
      "product": "golang-github-containerd-containerd-dev",
      "release": "Ubuntu 22.04.1 LTS (jammy)",
      "fixedVersion": "1.5.9-0ubuntu1",
      "fix": "golang-github-containerd-containerd-dev 1.5.9-0ubuntu1",
      "url": "https://patchblox.com/security/fix/linux/ubuntu-jammy-golang-github-containerd-containerd-dev-1.5.9-0ubuntu1",
      "released": "2022-01-05T11:15:00Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T06:59:42Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}