CVE-2021-43816

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 `/etc/hosts`, `/etc/hostname`, or `/etc/resolv.conf`. 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.

• CVE ID
• CVE-2021-43816

• Assigner
• security-advisories@github.com

• Vulnerability Status
• Analyzed

• Published Version
• 2022-01-05T19:15:08

• Last Modified Date
• 2022-04-01T14:50:57

• Version
• 2.0

• Vector String
• AV:N/AC:M/Au:S/C:P/I:P/A:P

• Access Vector
• NETWORK

• Access Compatibility
• MEDIUM

• Authentication
• SINGLE

• Confidentiality Impact
• PARTIAL

• Integrity Impact
• PARTIAL

• Availability Impact
• PARTIAL

• Base Score
• 6

• Severity
• MEDIUM

• Exploitability Score
• 6.8

• Impact Score
• 6.4

• Version
• 3.1

• Vector String
• CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

• Attack Vector
• NETWORK

• Attack Compatibility
• LOW

• Privileges Required
• HIGH

• User Interaction
• NONE

• Scope
• CHANGED

• Confidentiality Impact
• HIGH

• Availability Impact
• HIGH

• Base Score
• 9.1

• Base Severity
• CRITICAL

• Exploitability Score
• 2.3

• Impact Score
• 6