SIR.trading Transient Storage Bug

On March 30, 2025, the leveraged-trading protocol SIR.trading lost its entire TVL of ~$355,000 to a Solidity transient-storage (EIP-1153 tstore/tload) misuse. The protocol stored the expected Uniswap-v3 callback caller in transient storage but checked it incorrectly, letting the attacker pass the uniswapV3SwapCallback caller validation with a malicious contract.

What happened

SIR.trading used transient storage to track the authorized callback caller during a swap. A flaw in how the value was set/validated allowed an attacker to satisfy the callback's caller check from an arbitrary contract, then invoke the callback to extract the protocol's funds. The entire (small) TVL was drained.

Aftermath

• Protocol effectively ended; founder publicly distraught (the loss was 100% of TVL).

Why it matters

SIR.trading is one of the earliest exploits specifically of EIP-1153 transient storage — a 2024 EVM feature whose semantics (cleared at end of transaction, not call) are subtly different from regular storage and create a fresh footgun class. It is the newest instance of the catalogue's perennial theme: every new EVM primitive reintroduces caller-authentication bugs in a new form before the ecosystem's collective experience has hardened around it. Transient storage joins delegatecall, selfdestruct, ERC-777 hooks, and Uniswap-v4 hooks as primitives that were powerful, useful, and immediately the basis of an exploit.