Medium · published July 21, 2026
Trezor Safe 3, Safe 5, and Safe 7 firmware contains a confirmation-binding flaw in the Ethereum sign_tx / sign_tx_eip1559 flow. For contract interactions, the device confirms only the initial calldata chunk while the signature commits to the full streamed calldata. An attacker could present calldata to a victim then supply a different tail that changes the signed transaction. Fixed in 70c9b0c.