CVE-2026-43438

About vulnerability

In the Linux kernel, the following vulnerability has been resolved: sched_ext: Remove redundant css_put() in scx_cgroup_init() The iterator css_for_each_descendant_pre() walks the cgroup hierarchy under cgroup_lock(). It does not increment the reference counts on yielded css structs. According to the cgroup documentation, css_put() should only be used to release a reference obtained via css_get() or css_tryget_online(). Since the iterator does not use either of these to acquire a reference, calling css_put() in the error path of scx_cgroup_init() causes a refcount underflow. Remove the unbalanced css_put() to prevent a potential Use-After-Free (UAF) vulnerability. A flaw was found in the Linux kernel’s sched_ext component. This vulnerability is caused by a redundant css_put() call in the scx_cgroup_init() function, leading to a reference count underflow. This can result in a Use-After-Free (UAF) vulnerability, potentially allowing a local attacker to cause a denial of service or achieve privilege escalation.

Live-patch status from KernelCare for each operating system.