Executive brief
Ledger hardware wallets, used for securing cryptocurrency and digital assets, are susceptible to a flaw that can permanently disable the device. An attacker with physical access to the device during a firmware update could provide malicious instructions that cause the hardware to enter an unrecoverable error state. This results in a permanent loss of device operability, though the underlying private keys remain safe if the user has their recovery phrase.
Technical details
A denial of service vulnerability exists in the MCU firmware update mechanism of Ledger Nano X, Flex, and Stax devices due to improper validation of the 'reset_handler' parameter (CWE-1284). During the firmware flashing process, the device fails to verify that the provided reset handler address points to a valid and safe memory location. An attacker with physical access to the device can supply a crafted address pointing to invalid memory or malicious code. Upon the next boot cycle, the device attempts to execute from this invalid address, triggering a hardware fault that renders the device permanently inoperable (bricked). This issue is addressed in Nano X firmware 2.4.2, Flex firmware 1.2.2, and Stax firmware 1.6.2.
Affected products
- Ledger Nano X < 2.4.2
- Ledger Flex < 1.2.2
- Ledger Stax < 1.6.2
Timeline
- 2026-05-19: disclosed: Initial advisory publication