CVE-2026-99167

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

net/sched: fix use-after-free in tcf action put()

tcf action put() decrements the reference count before decrementing the binding count. Another thread can free the action between these operations, causing the binding-count update to access freed memory. KASAN reports it as:

BUG: KASAN: slab-use-after-free in tcf action put+0x327/0x340 Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64

Hold the action IDR mutex across both counter updates and IDR removal, keeping cleanup outside the lock.