Kernel-address disclosure via uninitialized nftables registers

Information disclosure in Linux Kernel 3.13-rc1 through 5.17 allows local users to read kernel stack data through nf_tables. The nft_do_chain routine leaves struct nft_regs uninitialized, so nftables expressions can expose residual kernel pointers and other stack contents. Exploitation requires local code execution and access to nf_tables, commonly obtained through enabled unprivileged user and network namespaces; the direct consequence is kernel-memory disclosure.