CVE-2026-98972

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

cgroup/cpuset: Don’t access cpuset_cgrp_subsys.root in is_in_v2_mode()

After seeing the patch [1] to guard is_in_v2_mode() with RCU, it makes me realize that is_in_v2_mode() may be called in a context where a new cgroup filesystem is being rebound with stale cpuset_cgrp_subsys.root pointer. Avoid this potential UaF situation by adding a new cpuset_v2_mode flag which is set when the cpuset_v2_mode mount option is used. This flag is written into only when cpuset_bind() is being called with a stable cpuset_cgrp_subsys.root value. The is_in_v2_mode() helper is modified to read the new cpuset_v2_mode flag instead of accessing cpuset_cgrp_subsys.root directly.

[1] https://lore.kernel.org/lkml/[email protected]

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Debian 10 ELS , Debian 11 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

linux-hwe @ 4.15.0 (+12 more)

Live-patch status from KernelCare for each operating system.