Ledger’s Ethereum App Flaws Explained: What OneKey Reproduced and Which Updates Fix Them

OneKey reproduced a genuine transaction-replacement vulnerability in Ledger’s older Ethereum app 1.22.1, but the test was conducted in a controlled lab environment. Ledger says the flaw had already been fixed in version 1.22.2 before the demonstration became public and that it found no evidence of attacks against users. 31731

The episode nevertheless exposed a broader issue: a hardware wallet’s security depends not only on its private-key isolation, but also on whether the device faithfully displays the transaction it ultimately signs.

What OneKey reproduced

The vulnerability, tracked by Ledger as LSB-023, involved command interleaving during an on-device transaction review. A host could submit a new APDU command while an earlier command was still awaiting the user’s response. Because signing parameters remained in shared state during that review, those parameters could potentially be changed after they appeared on the device but before the signature was produced. 3

In practical terms, the display could show transaction A while the device signed transaction B. OneKey’s Anzen team reproduced that behavior using the outdated 1.22.1 Ethereum app in a lab. That demonstrates exploitability of the old software; it does not demonstrate that Ledger’s production systems or users were compromised. 172332

Ledger says it had identified the vulnerability through its own security process and released safeguards in Ethereum app 1.22.2. Reporting also says the underlying issue was addressed in Secure SDK 26.6.1. 172124

Was anyone hacked?

Ledger’s statement was categorical: “No Ledger user was hacked.” The available reporting describes no known losses connected to OneKey’s reproduction, but that statement should be understood as a report about observed exploitation—not proof that exploitation would have been impossible on an affected version. 172031

The distinction matters. A lab reproduction can confirm that a vulnerable code path works under the required conditions without showing that criminals used it in the wild.

The two additional flaws fixed in version 1.22.3

Version 1.22.3 addressed two other Ethereum-app vulnerabilities that remained relevant after the 1.22.2 update. Ledger’s security bulletin index names them as LSB-024 and LSB-025. 46

LSB-024: a clear-signing batch could hide operations

LSB-024 concerned an integer or operation-count handling flaw in clear signing. A specially formed batch containing 257 operations could cause the device to display only the final operation while signing the entire batch.

That is a transaction-review integrity failure. The device may still require the user’s confirmation, but the information presented for review would not faithfully describe the complete payload being signed. Ledger lists the issue as “Clear-signing bypass via array-count truncation.” 46

LSB-025: a swap payment could become a token approval

LSB-025 affected a swap flow. A compromised swap provider could substitute a token approval for the expected payment without triggering another device prompt. Ledger describes it as “Swap flow accepted a token approval in place of a payment.” 46

The reported limits are important. This was not described as a mechanism for creating an unlimited allowance or approving an arbitrary attacker-selected address. It could nevertheless cause a user to sign an approval they did not intend to authorize, which is materially different from the expected payment in a swap. 46

Why were LSB-024 and LSB-025 not included in 1.22.2?

The public material supplied for this report indicates that the relevant changes for the two later flaws had reportedly been merged months before version 1.22.2 shipped, yet the fixes appeared in 1.22.3 instead. Reporting describes the omission as an unresolved release or integration question. 37

There is not enough authoritative public documentation here to establish whether the cause was release prioritization, integration failure, testing, or another internal decision. The defensible conclusion is narrower: the fixes were not included in 1.22.2, and the precise reason remains publicly unexplained. Stronger claims would go beyond the available evidence.

What the incident says about Ledger’s updateable security model

Ledger’s response emphasized that an updateable wallet architecture allows vulnerabilities in device applications and supporting software to be corrected and distributed. In that model, the security process is intended to identify a flaw, develop a fix, release it, and disclose the issue with technical details afterward. LSB-023 was presented as an example of that process: the flaw was identified internally, patched, and later documented in a security bulletin. 3

That argument has a clear benefit: a discovered software vulnerability does not necessarily remain permanent. But it also creates an operational requirement for users. A patch only protects a device after the affected application has actually been updated, and a delayed or incomplete release can leave related issues unresolved—as the gap between 1.22.2 and 1.22.3 illustrates. 37

What Ledger users should do

1. Update the Ethereum app to version 1.22.3 or later. Reporting identifies 1.22.3 as the release that addressed LSB-024 and LSB-025, while 1.22.2 contained the app-level fix for LSB-023. 1737
2. Use Ledger Live’s device manager and official Ledger distribution channels for application updates. Ledger’s setup guidance directs users to install the Ethereum app through Ledger Live. 7
3. Review every prompt on the device, especially during swaps. If the device requests an approval when you expected a payment, stop and reject the operation.
4. Be cautious with unusually large or opaque batches. Avoid blind signing where possible, particularly when the full payload cannot be meaningfully reviewed on the device.
5. Treat connected hosts and providers as part of the threat model. The vulnerabilities involved the communication boundary between a host or service and the Ledger application, so a hardware wallet does not eliminate risks from malware, hostile webpages, compromised dApps, or swap providers. 328
6. Review allowances after using affected software. If you performed swaps or signed approvals while running a vulnerable app version, check for unnecessary token allowances and revoke them through a trusted interface.

The immediate takeaway is straightforward: OneKey demonstrated a real flaw in an outdated Ledger Ethereum app, but the available evidence does not show a live Ledger hack. Users should still treat the incident seriously, because LSB-024 and LSB-025 show that updating to the first available fix was not necessarily the end of the security story.