CVE-2026-98487 net: bridge: mdb: restart port group walk after deletion

In the Linux kernel, the following vulnerability has been resolved: net: bridge: mdb: restart port group walk after deletion brmdbflushpgs keeps a pointer-to-pointer cursor while walking mp-ports. brmulticastdelpg can re-enter the same MDB entry through brmulticastsgdelexcludeports and unlink oth...