Zilliqa Warns of Ledger App Flaw That Can Expose Private Keys From Native Transaction Signatures

Zilliqa has disclosed a critical security issue in its Ledger application that impacts Schnorr signature generation for native (non-EVM) Zilliqa transactions, according to ME News. The vulnerability affects every version of the Zilliqa Ledger app released from 2019 through 2026. The project said it detected on-chain signs of suspected active exploitation on July 19 (UTC+8) and confirmed the root cause on July 21. The bug makes it possible for an attacker to predict the ephemeral nonce used during signature creation. With only publicly available on-chain data, this predictability can allow an attacker to reconstruct the signer's private key. Zilliqa is urging users who previously signed native Zilliqa transactions using Ledger devices to wait for official instructions and avoid taking any independent action. Zilliqa attributed the flaw to the signing program copying the wrong byte range when writing the nonce into a buffer. As a result, the highest 64 bits of every generated nonce are fixed to zero, sharply reducing entropy. With five or more affected signatures, attackers can recover the private key in seconds using lattice reduction techniques. Because the impacted signatures are permanently recorded on-chain, a Ledger app update cannot eliminate the exposure. Zilliqa said any associated private keys must be discarded. Native transactions have been temporarily suspended to prevent additional losses, and the project said it is finalizing a coordinated remediation plan. Zilliqa noted that EVM transactions are not affected, and neither are SDKs including zilliqajs, gozilliqasdk, and pyzil. (Source: Foresight News)