Ledger has fixed a vulnerability in certain Ethereum transaction-signing flows that could have allowed a malicious decentralized application to substitute a transaction while a user was reviewing it. The issue affects the security boundary between a dApp and Ledger’s Ethereum signing process, where users rely on the hardware device to confirm the transaction they intend to authorize.
The vulnerability was publicly reported on Aug. 24 after security researchers identified a race-condition flaw in the Ethereum app’s signing flow. Reports indicate that an attacker could potentially exploit the signing process so the device displayed one transaction while signing another.
How the attack could work
The risk centered on the period between transaction review and final approval. A malicious dApp with access to the device connection could attempt to introduce different transaction data during that window.
That scenario could undermine one of the core protections of a hardware wallet: allowing users to verify transaction details on a trusted device before signing. Ledger’s Ethereum tooling emphasizes human-readable transaction information through its Clear Signing architecture, designed to make approvals easier to verify.
Security reports say the vulnerability was reported to Ledger on Aug. 21, with researchers validating the behavior on a Ledger device. The issue was subsequently addressed in an Ethereum app update.
Users should update before signing
Ledger users who interact with Ethereum dApps should update Ledger Wallet and install the latest Ethereum app available for their device. Users should also continue checking transaction details directly on the hardware wallet before approving.
The vulnerability does not mean Ledger devices were generally compromised or that private keys were exposed. Instead, the reported issue concerned the integrity of transaction data presented during a particular signing flow.
The incident also highlights why transaction verification remains important even with hardware wallets. Ethereum’s broader Clear Signing initiative aims to improve that verification layer by showing users understandable transaction details rather than opaque contract data.
