Symbiosis said an attacker exploited its native Bitcoin Bridge at about 04:28 UTC on September 11, 2026, isolating the affected component while the protocol kept other cross-chain services operating. On-chain monitors said a signed BridgeV2 receive minted about 2^62 raw syBTC, or roughly 46.1 billion tokens at face value, to a new BNB Chain wallet. Blockaid identified sales of about 4.39 WBTC on Uniswap v4 that generated roughly $336,000, but that realized-proceeds figure is not Symbiosis' confirmed loss. The protocol recovered approximately 15 BTC in a team-controlled multisignature wallet, though it has not published a recovery transaction, wallet address, final loss figure or technical post-mortem. Its 20% white-hat bounty window closed on September 13 without public confirmation that the attacker responded. The native bridge remains paused, while Bitcoin swaps through Chainflip and THORChain have resumed. Symbiosis says it is contacting affected liquidity providers and preparing compensation criteria, which remain unpublished. The breach was the third recent incident involving unbacked Bitcoin-linked tokens, following attacks affecting Liquid Network and Nomic.