Symbiosis Bitcoin bridge flaw used to mint $46.1B in syBTC; $336K cashed out

Odaily Planet Daily reports that onchain security firm Blockaid identified a vulnerability in the Bitcoin bridge used by crosschain protocol Symbiosis. The attacker minted roughly 2^62 syBTC into newly created externally owned accounts. Using an eight-decimal convention, the notional value was calculated at about $46.1 billion. The attacker then swapped about 4.39 WBTC on Uniswap V4 on Ethereum, withdrawing approximately $336,000. Symbiosis said the incident took place around 4:28 a.m. on Sept. 11. The team has paused BTC routing, while stating that other routes remain operational and unaffected. Symbiosis also said it recovered about 15 BTC and moved the funds to a team-controlled multisig wallet. A 20% whitehat bounty has been offered to the attacker with a Sept. 13 deadline. The report notes that recent weeks have seen multiple incidents involving token minting without real asset backing, including cases affecting Liquid Network, Nomic, and Symbiosis. As of Sept. 13, Symbiosis had not publicly released a technical post-mortem for BridgeV2, disclosed the final loss figure, or confirmed whether the attacker accepted the bounty. (Bitcoin.com News)