CVE-2021-4197

Published: 31 December 2021

An unprivileged write to the file handler flaw in the Linux kernel's control groups and namespaces subsystem was found in the way users have access to some less privileged process that are controlled by cgroups and have higher privileged parent process. It is actually both for cgroup2 and cgroup1 versions of control groups. A local user could use this flaw to crash the system or escalate their privileges on the system.

From the Ubuntu security team

Eric Biederman discovered that the cgroup process migration implementation in the Linux kernel did not perform permission checks correctly in some situations. A local attacker could possibly use this to gain administrative privileges.

Priority

Medium

CVSS 3 base score: 7.8

Status

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-4197
• https://lore.kernel.org/lkml/20211209214707.805617-1-tj@kernel.org/T/
• https://bugzilla.redhat.com/show_bug.cgi?id=2035652
• https://ubuntu.com/security/notices/USN-5278-1
• https://ubuntu.com/security/notices/USN-5337-1
• https://ubuntu.com/security/notices/USN-5368-1
• NVD
• Launchpad
• Debian

Bugs