Zilliqa Halts Native Transactions After Ledger App Flaw Exposes Private Keys

Zilliqa has halted native ZIL transactions following the invention of a vital vulnerability within the community’s Ledger software, which permits the personal keys of sure accounts to be recovered from public signatures on the blockchain. The incident was disclosed after an undisclosed quantity of ZIL was stolen from an change companion’s chilly pockets, forcing the challenge to request centralized platforms to pause ZIL deposits and withdrawals to curb the motion of funds. 

In keeping with Zilliqa, the flaw lies within the native transaction signing course of utilizing the Ledger app and doesn’t have an effect on EVM transactions or official SDKs. The challenge acknowledged that the vulnerability had existed in app variations relationship again to 2019, with on-chain exploitation indicators detected on July 19, 2026, two days earlier than the foundation trigger was remoted.

Change Theft and Preliminary Response

Zilliqa publicly disclosed the incident on July 20, stating that an undisclosed quantity of ZIL had been stolen from an change companion’s chilly pockets. On the time, the challenge didn’t specify the technical trigger or the size of damages, noting that an investigation was ongoing to find out the foundation trigger and the scope of influence.

Now we have been made conscious of a safety incident involving certainly one of our change companions, during which ZIL was stolen from a chilly pockets.

The incident is underneath energetic investigation, and we’re working with the related events to ascertain the foundation trigger and full scope. As a…

— Zilliqa (@zilliqa) July 20, 2026

Exchanges had been subsequently notified and requested to pause ZIL deposits and withdrawals as a precautionary measure to forestall the stolen funds from being transferred or bought by means of centralized platforms whereas the verification course of continued. 

On July 21, Zilliqa up to date that it discovered no proof suggesting the incident originated from pockets administration procedures or operational actions of the change. The investigation then shifted to a technical difficulty affecting transaction signing in a gaggle of legacy ZIL1 wallets, earlier than the challenge disclosed detailed details about the vulnerability within the Zilliqa Ledger app a day later.

Affected Wallets and Transaction Scope

Zilliqa restricted the scope of influence to personal keys that had been used to signal native Zilliqa transactions by way of a Ledger machine. In keeping with the challenge’s advisory, accounts which have broadcast roughly 5 or extra native transactions utilizing the Zilliqa Ledger app needs to be thought-about compromised. 

This threat applies to signatures already publicly recorded on-chain, that means subsequent software program updates can not reverse the publicity stage of affected personal keys. Customers with accounts on this group should cease utilizing the compromised keys, quite than merely updating the transaction-signing app. 

EVM transactions are unaffected, whereas transactions signed by means of official SDKs equivalent to zilliqa-js, gozilliqa-sdk, and pyzil are additionally exterior the scope of the flaw. The incident is due to this fact remoted to the native signing path of the Zilliqa Ledger app. 

Zilliqa has not disclosed the quantity of ZIL stolen, the variety of affected accounts, or the entire worth of property held in weak addresses. Consequently, the general monetary extent of the incident stays unclear.

Ledger App Vulnerability

The basis trigger lies in how the Zilliqa Ledger app generates nonces for EC-Schnorr signatures on the secp256k1 curve. For every signature, the app must generate a recent, random, and unpredictable 256-bit nonce; if the nonce is biased or lacks entropy, a number of signatures can expose the personal key. 

The app’s signing routine generates 40 bytes of randomness after which reduces this worth modulo the order of the curve to provide a 256-bit quantity. Nevertheless, when copying the end result into the nonce buffer, the code mistakenly extracted 32 bytes from the 40-byte output, retaining 8 bytes of zero-padding whereas discarding 8 bytes of entropy. 

This flaw leaves the 64 most important bits of every nonce mounted at zero. With roughly 5 or extra affected signatures, the personal key might be recovered in seconds on commodity {hardware} utilizing Hidden Quantity Downside fixing and lattice discount methods.

Native Transaction Halt

Zilliqa halted native non-EVM transactions as a protecting measure whereas finalizing a remediation plan. The transfer goals to forestall additional asset losses from weak accounts whereas limiting the motion of stolen ZIL by means of the native transaction movement. 

Affected accounts can’t be protected by a typical switch transaction both. If a non-public key can already be recovered from on-chain knowledge, an attacker holding the identical key can detect and front-run the consumer’s asset switch transaction. Subsequently, making an attempt to maneuver funds independently could also be ineffective and improve threat, whereas EVM transactions proceed to stay unaffected.

Remediation Plan and Consumer Steering

A hard and fast construct of the Ledger app is being ready in coordination with Ledger. This repair will restore the complete nonce era course of to forestall the app from creating additional weakened signatures sooner or later. Nevertheless, the patch can not reverse the danger for personal keys which have already signed the required variety of affected native transactions beforehand. 

Keys belonging to the affected group in the end should be retired from use. Zilliqa is finalizing a remediation plan to safeguard balances in related accounts and can publish separate directions for customers who’ve signed native Zilliqa transactions utilizing Ledger. Till official steering is offered, customers are suggested to not act independently and to observe solely the challenge’s official channels. 

KuCoin was credited by Zilliqa for helping in figuring out the foundation trigger throughout the Ledger app’s nonce era course of, recovering affected personal keys from on-chain knowledge, and confirming ongoing exploitation exercise. Nevertheless, Zilliqa has not publicly confirmed whether or not KuCoin was the change companion that misplaced ZIL within the preliminary announcement.