CVE-2026-74748 netfilter: ipset: fix refcount race between list:set GC and swap

In the Linux kernel, the following vulnerability has been resolved: netfilter: ipset: fix refcount race between list:set GC and swap ipsetputbyindex resolved the index to a set pointer under RCU, then took ipsetreflock in ipsetput to decrement set-ref. ipsetswap holds that same lock while swappin...