CVE-2026-72227 batman-adv: mcast: avoid OOB read of num_dests header

In the Linux kernel, the following vulnerability has been resolved: batman-adv: mcast: avoid OOB read of numdests header Before the access to struct batadvtvlvmcasttracker's numdests, it is attempted to check whether enough space is actually in the network header. But instead of using offsetofend...