Hardware wallet security is back in the spotlight after open-source wallet provider OneKey announced that its in-house security team successfully reproduced an exploit targeting an outdated version of Ledger’s on-device Ethereum application in a laboratory environment. The demonstration, confirmed by OneKey founder and CEO Yishi Wang, highlights how a previously patched vulnerability could have allowed attackers to overwrite a transaction while a user was still reviewing it on screen.
According to Wang, the OneKey team executed what it calls a “transaction replacement attack” against version 1.22.1 of the Ledger Ethereum app. The attack exploited a flaw that had already been fixed by Ledger, but which remains dangerous for any users still running older software on their devices. The core of the problem lies in how the device handles the signing queue: under specific conditions, a malicious actor with sufficient control over the communication channel between the hardware wallet and the host computer could swap out the legitimate transaction waiting to be signed and replace it with a different one — all while the victim believes they are approving the original transfer.
How the Attack Works
The vulnerability does not involve breaking the device’s secure element or extracting private keys. Instead, it targets the session between the wallet and the computer or smartphone it is connected to. If an attacker can control that communication channel — through malware installed on the host machine, compromised wallet software, or even a hostile webpage — the attacker can manipulate what data reaches the device during the signing process.
In the scenario reproduced by OneKey, the user begins reviewing a legitimate transaction on the Ledger screen. While that review is in progress, the attacker pushes a replacement transaction into the signing queue. Depending on the app version and timing, the device may ultimately sign the attacker’s transaction instead of the one the user intended to approve. For users who carefully verify every address and amount before confirming, this class of attack is particularly troubling because it attacks the review process itself rather than the user’s habits.
Ledger’s Response
Ledger moved quickly to address the issue in two stages. The company first introduced app-level safeguards with the release of its Ethereum app version 1.22.2 on August 13, which blocked the replacement technique at the application layer. Days later, on August 21, Ledger shipped Secure SDK 26.6.1, which fixed the underlying issue in the device firmware layer itself.
The company also pushed back against any suggestion that customers had been harmed. “No Ledger user was hacked. What’s described here is a lab reproduction of a vulnerability in an outdated version of the Ethereum app,” Ledger wrote in a post on X, formerly Twitter, on Thursday. Ledger emphasized that exploiting the vulnerability required control over communications between the device and its host — a condition that typically presupposes an already-compromised computer or a sophisticated man-in-the-middle setup.
The company further clarified that anyone running current versions of its applications is protected against the demonstrated technique, and it encouraged all users to verify that their Ethereum app and device firmware are fully up to date.
Context: A Summer of Hardware Wallet Scrutiny
The OneKey demonstration lands amid an unusually active period for hardware wallet security research. In July, attackers exploited a firmware bug in Coinkite’s Coldcard devices that had been introduced in March 2021. That flaw weakened the randomness used during seed generation on certain units, leaving the resulting private keys vulnerable to brute-force attacks. Investigators later linked the stolen funds — which included tens of Bitcoin and hundreds of Ether — to cryptocurrency mixing services as the attackers attempted to launder the proceeds.
At the time, Ledger publicly stated that its devices were not affected by the Coldcard vulnerability because its recovery phrases are generated using a certified source of randomness built into the device’s dedicated security chip. The flaw reproduced by OneKey is a separate matter entirely: it is unrelated to seed generation and instead affects how transactions are handled during the signing process itself.
Lessons for Users
Security researchers broadly agree on several takeaways from the incident. First, keeping wallet applications and firmware current is not optional hygiene — it is the single most effective defense against this exact class of attack, since both the app-level and firmware-level fixes ship through standard update channels. Second, users should treat their host computers as part of their threat model. A hardware wallet does not sterilize a compromised machine; malware on the host remains a powerful attack vector, as the preconditions for this exploit demonstrate.
Third, the incident is a reminder that responsible disclosure and independent reproduction play an essential role in the ecosystem’s security. OneKey’s lab work did not expose live users to risk — Ledger had already patched the issue — but it validated that the fix works as intended and gave the community a concrete, documented understanding of what the attack would have looked like in practice.
For now, no user funds are reported lost, and current Ledger software is considered protected against the demonstrated technique. But the episode reinforces a familiar maxim in hardware wallet security: the safest device is not the one with the best marketing — it is the one with the latest firmware.
Disclaimer: This article is for informational purposes only and does not constitute financial advice.
onekey publishing the exact firmware version that breaks is better disclosure than most auditors manage. update past 1.22.1 and move on
Still running 1.22.1 on my Nano S because updating felt like a chore. Updating tonight. This is exactly the kind of thing people ignore until funds move.
nano s plus auto updated and i still rechecked the version twice lol. blind signing off too, not risking the swap attack
same energy as people who never update their node. the attack swaps the tx mid review, so even checking the address on screen doesnt save you on old firmware
while you are in there toggle blind signing off too. the swap attack needs the stale app but blind signing is what makes the whole genre of trick possible
this should be the pinned comment honestly. stale app plus blind signing is the full combo, one alone usually fails
blind signing off breaks defi flows for most users tho, thats why people leave it on. queue clearing in 1.22.2 was the real fix
scariest part is you don’t need to break the secure element, just own the channel between wallet and computer. update your Ledger eth app people, 1.22.1 is literally the version they named
Exactly. Malware on the host swapping the tx while you stare at a screen you thought you could trust. Blind signing off, app updated, still not fully relaxed
this is the part people miss. the secure element never broke, your infected laptop did. update the app and stop using sketchy usb cables
updated mine the second i saw 1.22.1 named specifically. fix has been out for months and people still run stale apps, wild
OneKey doing free security audits for the competition now lol. Jokes aside, respect to Yishi Wang’s team for publishing the reproduction instead of sitting on it
better this than some random researcher finding it after funds vanish. still waiting for Ledger Live to nag way harder about stale app versions though
ledger live nags about marketing emails harder than stale firmware. priorities
lol accurate. the device does warn about outdated firmware before signing, people just mash through it
lmao ledger live nagged me three times about the recover subscription but the stale eth app got a single quiet banner. priorities indeed
OneKey doing free security research on a competitor and publishing it is good for everyone. Hopefully Ledger sends them a bounty anyway.
ledger should cut that bounty check today. onekey naming firmware 1.22.1 exactly is doing more for nano owners than the last three official announcements combined
I tested the 1.22.1 version myself last month just to see if the vulnerability was real. Its terrifying how easily the transaction can be swapped if youre not paying full attention to every detail on the display.
Same issue with other hardware wallets too. Ive seen cases where people sign transactions with outdated firmware and wonder why their funds disappear later. This is exactly why regular updates arent optional.
you tested it yourself last month and only mention it now? convenient timing if you ask me
OneKey reproducing an already patched flaw just to prove the residual risk is the kind of disclosure this industry needs. naming the exact version leaves zero ambiguity
the fix shipped months ago and the repro only works because someone deliberately kept a stale eth app installed. solid research, non news
non news until you check how many people actually updated. ledger telemetry would tell us but they wont publish that number
Competitor security teams doing free audits of your product is honestly the best deal ledger ever got. Everyone wins except the guy still running firmware from 2024.
Ledger paying a bounty for research they already fixed would just be PR. the patch exists, the actual problem is millions of devices still running the old app