Ledger Donjon Discloses Vulnerability in Trezor TROPIC 01 Chip

Tropic Square, the chipmaker, published the finding jointly with Ledger on 3 Jun. Trezor said in a statement that user funds remain safe. Even a fully successful attack on TROPIC01 in isolation does not give an attacker the user's PIN or access to funds, it added.

"Trezor Safe 7 was built to include TROPIC01, an open and auditable secure element, so its security could be independently verified," said Matej Žák, CEO of Trezor. 

"The device itself was designed with multiple independent security layers so that no single component is a single point of failure. Both decisions matter today." 

What is at risk?

The TROPIC01's firmware source code and hardware design are both publicly available, allowing Ledger's researchers to use the published code to map the exact verification routine they would need to disrupt, in the same way an attacker might. 

The technique Ledger Donjon used to expose the weakness - laser fault injection - involves firing a precisely timed pulse at the chip's exposed silicon to trick it into accepting unsigned, potentially malicious firmware as legitimate. 

"I believe the open process by which this vulnerability was found, examined and disclosed is the model the industry should hold itself to," Žák said.

While a vulnerability was exposed, it required specialist equipment and access to the hardware wallet, leading to a risk rating of medium (5.7), the companies said. There has been no mention of evidence of real-world exploitation. 

Tropic Square has issued a security advisory recommending that partners disable maintenance mode on deployed devices as an interim measure while the new silicon revision is developed.

Open-source transparency

Trezor said the disclosure is being published proactively because "this is how open-source security should work."

"Without transparency, users have no way to know whether the technology in their hardware wallet is at risk, because the manufacturer is not free to disclose what is found," the firm said.

Ledger's team first cracked the chip on 26 Jan and disclosed the finding to Tropic Square the following day. Tropic Square confirmed the vulnerability and has worked with Ledger on testing mitigations. The parties agreed in May to publish jointly on 3 Jun.

Corrective action

Ledger Donjon noted that Tropic Square "acknowledged the vulnerability promptly, engaged in substantive technical discussion... and moved quickly toward a remediation plan."

Following Ledger's initial disclosure, Tropic Square's own engineers identified a secondary vulnerability affecting the chip's MAC-and-Destroy mechanism, the hardware function that underpins PIN verification in the Safe 7. 

Full technical details of that second finding will be withheld until spring 2027, pending a hardware fix. A hardened silicon revision is expected by late 2026.