A vulnerability in the Linux kernel's netfilter nft_byteorder feature involves broken 64-bit byteorder conversion when multiple registers are converted simultaneously. The issue arises because the source register array advances incorrectly in 4-byte steps instead of 8, causing dysfunctional multi-register byteorder conversions. The problematic multi-register support has been removed to simplify the code and avoid incorrect conversions. This affects nftables before version 1.1.0, which can generate incorrect byteorder conversions and cause affected rulesets to fail to load due to length mismatches.