Bug in multisig verification

Incorrect on-device display/confirmation could have misled users into approving a seemingly minor “fee bump” transaction that was actually malicious, potentially compromising funds in a Bitcoin multisig wallet (threshold > 1). The attacker would need to control one signer, and the other signers’ Trezor Suite would need to be compromised.

In addition to this finding, the researcher submitted several minor reports spanning Firmware, Suite, Connect, and Blockbook. Many of the findings were low severity and focused on robustness and hardening issues such as out-of-bounds reads, parsing/validation bugs, verifier/bypass edge cases, memory-zeroization gaps in cryptography code paths, and transport/protocol handling problems. As these were primarily low-severity or purely informative, they have not been listed here individually. We sincerely thank the researcher for their comprehensive contributions.