On July 30, 2026 an attacker used Swan Treasury's leaked off-chain signer key to generate valid signatures with the discount parameter set to 1, buying ~687,000 STY on BNB Chain at roughly 1/100 of intended price using a ~19,700 USDT PancakeSwap flash loan, then dumping the tokens for a ~$625K protocol loss.

The decentralized asset management protocol Swan Treasury on BNB Chain was exploited due to the leakage of an off-chain signer's private key (the _signer key hardcoded in the ZhaiquanBuy contract). The attacker forged valid signatures and used PancakeSwap flash loans to purchase approximately 687,000 STY tokens at around a 100x discount (spending approximately 19,700 USDT). The attacker then forged the related claim()/transfer signatures and dumped the tokens into the STY/USDT pool, making a profit of approximately $625,000.