MANTRA Chain has resumed producing blocks after a roughly 30-hour interruption that left its mainnet unable to process transactions. The network restarted at about 5:30 a.m. UTC on Aug. 22 after deploying version 8.4.0, which the team said patched a Cosmos-EVM vulnerability and added further security protections.

According to MANTRA, the incident affected two wallets managed by the project, but user balances did not change and no user funds were exploited. The chain was brought back online without a rollback or any change to network state, and token holders were told they did not need to take action.

How the outage unfolded

The disruption began late on Aug. 20, when MANTRA said it detected an attacker exploiting a vulnerability in an upstream software dependency used by the blockchain. Developers then halted the mainnet so transactions would no longer be processed while security teams investigated the issue.

During the stoppage, transactions and network endpoints were frozen. Transfers, staking, bridges, and inter-blockchain communication relays were paused, and some exchanges temporarily stopped deposits and withdrawals. MANTRA said the chain remained at block 17,449,398 while the review was underway.

What MANTRA says was affected

The team traced the problem to its Cosmos-EVM module, the part of the system that supports Ethereum-compatible smart contracts. MANTRA said two wallet addresses were affected before the threat was contained.

The project added that there was no indication user, exchange, or partner funds were directly impacted. It said no user funds were exploited, and balances on the network remained unchanged throughout the incident.

Coordinated restart with v8.4.0

Before restarting the chain, MANTRA said it took a complete snapshot of the halted blockchain. The recovery then relied on a coordinated software update across MANTRA-operated validators and other members of the validator set.

Version 8.4.0 was tested on the DuKong testnet and in an internal environment designed to mirror mainnet conditions. Validators upgraded in sequence before block production resumed through the patched release. Public RPC and EVM endpoints were restored after the restart, although MANTRA noted that explorers and some related services could lag while catching up on post-restart data.

Open questions around the vulnerability

The outage has drawn attention to a Cosmos Labs vulnerability disclosed in March 2026 involving the ICS20 precompile. Cosmos Labs had said the flaw could allow token balances to be reused repeatedly within a single transaction, and noted that 15 chains were running code with the issue.

A permanent fix for that vulnerability was later included in Cosmos EVM version 0.6.0, with affected networks said to have upgraded or mitigated. It remains unconfirmed whether the Aug. 20 incident on MANTRA exploited that same flaw.

What comes next

MANTRA introduced EVM support in September 2025 alongside CosmWasm, allowing developers to build in either environment on the network. The chain is focused on tokenized real-world assets and is tied to institutional projects, including an agreement announced by Inveniam Capital Partners to acquire MANTRA and its affiliated entities after a $20 million strategic investment in August 2025.

The MANTRA token briefly fell to a record low around Aug. 20 as trading activity climbed, but any direct link between that move and the attack has not been confirmed. The project said it plans to publish a full post-incident report in the coming days covering the Cosmos-EVM vulnerability and its response.

Source: crypto.news