A security study found 31 previously unknown vulnerabilities in 15 major facilitators that support the x402 HTTP‑native payment standard, covering about 99% of observed transactions. x402 is an HTTP‑native standard that enables programmatic crypto payments. Facilitators act as intermediaries that verify payment proofs, construct settlement transactions, and often sponsor network fees. The research examined 15 facilitators representing 99% of observed x402 transactions. Each facilitator failed at least one of eight payment‑verification or settlement rules, resulting in 49 violation instances classified into four attack categories: free shopping, asset theft, service denial, and gas abuse. Two free‑shopping attacks were demonstrated end‑to‑end. Ten additional cases were deemed high risk because loss depended on merchant actions after verification. The analysis also identified three gas‑abuse cases and one asset‑theft path linked to ERC‑6492. Researchers executed a proof of concept that triggered a token approval but did not complete a transfer or steal funds. The study estimated that across more than 119 million Base and Solana transactions from October 1 to December 26 2025, about $202,000 in gas and fees were incurred, including roughly $5,800 from transaction reverts. All 15 facilitators exhibited high‑risk service‑denial or cost‑amplification paths; however, no outage or gas‑drain test was performed. The authors disclosed findings to 14 of 15 affected parties in January. As of February 6, Coinbase, PayAI and Mogami had acknowledged six vulnerabilities and applied fixes, while work on the remaining issues continued. Because the paper anonymizes the specific mapping of fixes to vendors, it does not indicate which fixes correspond to each party. The authors recommend binding verification to settlement, reserving nonces, rechecking time and account state, allowing only ERC‑1271 and ERC‑6492 transaction shapes, limiting sponsored fees, and rejecting uneconomic or non‑settleable payments. Merchants are advised to release services only after successful settlement or to implement explicit rollback mechanisms. The findings highlight the need for stronger controls around intermediaries in x402 payment flows before broader adoption.