Wu said he learned that on September 6, the Liquid Network suffered a Rangeproof verification cached-key collision vulnerability attack. The attacker minted approximately 3,998.5 L-BTC without the corresponding BTC inflow (peg-in), and then within a few minutes exchanged it via peg-out for BTC on the Bitcoin mainnet. After that, about 3,400 BTC was returned to the Liquid federation’s linked wallet, while approximately 598.5 BTC remained under the attacker’s control. The SlowMist report says the vulnerability stems from Elements failing to include a length prefix when concatenating multiple variable-length fields while constructing the Rangeproof verification cached key, allowing different parameter combinations to produce the same cached key. By crafting transactions to trigger a cached collision, the attacker caused nodes that hit the cached result marked “verification passed” to skip secp256k1_rangeproof_verify and the minimum-amount check, thereby accepting outputs not backed by real assets and completing the L-BTC minting. SlowMist has tracked the Bitcoin-side fund flows and completed incident analysis.