Zebra has sync restart poisoning from single unauthenticated peer via above-lookahead block
A malicious peer can answer Zebra's outbound getblocks/FindBlocks request with a small two-hash inventory, then serve a syntactically valid block whose coinbase height is far above the victim's local tip. The AboveLookaheadHeightLimit error in the sync download pipeline triggers a global sync restart rather than being scoped to the offending peer. The peer is never scored or disconnected because the error type does not carry the advertiser address. On mainnet, …