CVE-2026-64036 cgroup/rstat: validate cpu before css_rstat_cpu() access

In the Linux kernel, the following vulnerability has been resolved: cgroup/rstat: validate cpu before cssrstatcpu access cssrstatupdated is exposed as a BPF kfunc and accepts a caller-provided cpu argument. The function uses cpu for per-cpu rstat lookups without checking whether it refers to a...