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OpenAdvisories
High USN-6088-2 6 CVEs

runc vulnerabilities

Published May 23, 2023 · Updated Jun 25, 2026

Summary

USN-6088-1 fixed vulnerabilities in runC. This update provides
the corresponding updates for Ubuntu 16.04 LTS.

It was discovered that runC incorrectly performed access control when
mounting /proc to non-directories. An attacker could possibly use
this issue to escalate privileges.
(CVE-2019-19921)

Felix Wilhelm discovered that runC incorrecly handled netlink
messages. An attacker could possibly use
this issue to escalate privileges. (CVE-2021-43784)

Andrew G. Morgan discovered that runC incorrectly set
inherited process capabilities inside the container.
An attacker could possibly use this issue to
escalate privileges. (CVE-2022-29162)

Original advisory details:

It was discovered that runC incorrectly made /sys/fs/cgroup
writable when in rootless mode. An attacker could possibly
use this issue to escalate privileges. (CVE-2023-25809)

It was discovered that runC incorrectly performed access control when
mounting /proc to non-directories. An attacker could possibly use
this issue to escalate privileges. (CVE-2023-27561)

It was discovered that runC incorrectly handled /proc and
/sys mounts inside a container. An attacker could possibly
use this issue to bypass AppArmor, and potentially SELinux.
(CVE-2023-28642)

Fixed packages 1

ReleasePackageFixed in
Ubuntu · Pro 16.04 LTS Pro:16.04:LTS runc 1.0.0~rc7+git20190403.029124da-0ubuntu1~16.04.4+esm4

Vulnerabilities 6

  • High 7.0

    Opencontainers runc Incorrect Authorization vulnerability

    runc through 1.1.4 has Incorrect Access Control leading to Escalation of Privileges, related to libcontainer/rootfs_linux.go. To exploit this, an attacker must be able to spawn two containers with custom volume-mount configurations, and be able to run custom …

  • Medium 6.1

    AppArmor bypass with symlinked /proc in runc

    runc is a CLI tool for spawning and running containers according to the OCI specification. It was found that AppArmor can be bypassed when `/proc` inside the container is symlinked with a specific mount configuration. This issue has been fixed in runc version…

  • Medium 6.0

    Overflow in netlink bytemsg length field allows attacker to override netlink-based container configuration

    runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc, netlink is used internally as a serialization system for specifying the relevant container configuration to the `C` portion of the code (responsible f…

  • Medium 5.9

    opencontainers runc contains procfs race condition with a shared volume mount

    runc through 1.0.0-rc9 has Incorrect Access Control leading to Escalation of Privileges, related to libcontainer/rootfs_linux.go. To exploit this, an attacker must be able to spawn two containers with custom volume-mount configurations, and be able to run cus…

  • Medium 5.9

    Incorrect Default Permissions in runc

    runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. A bug was found in runc prior to version 1.1.2 where `runc exec --cap` created processes with non-empty inheritable Linux process capabilities, creating an aty…

  • Medium 5.0

    rootless: `/sys/fs/cgroup` is writable when cgroupns isn't unshared in runc

    runc is a CLI tool for spawning and running containers according to the OCI specification. In affected versions it was found that rootless runc makes `/sys/fs/cgroup` writable in following conditons: 1. when runc is executed inside the user namespace, and the…

References

  • report
    https://ubuntu.com/security/CVE-2019-19921
  • report
    https://ubuntu.com/security/CVE-2021-43784
  • report
    https://ubuntu.com/security/CVE-2022-29162
  • report
    https://ubuntu.com/security/CVE-2023-25809
  • report
    https://ubuntu.com/security/CVE-2023-27561
  • report
    https://ubuntu.com/security/CVE-2023-28642