DeFi in Turmoil: Penpie Loses $27M to Reentrancy Attack, Synthetix Unveils SNAXChain, Japan Banks Launch Stablecoin Trial

September 2024 is shaping up to be one of the most eventful months for decentralized finance in recent memory. As the broader crypto market reels from a sharp sell-off — with Bitcoin and Ethereum both down more than 9% on the weekly chart — the DeFi sector is grappling with a major security breach, a landmark protocol expansion, and institutional adoption milestones from Asia. Here’s a comprehensive look at the stories dominating the DeFi landscape on September 6, 2024.

TL;DR

• Penpie exploited for $27 million — A reentrancy vulnerability in the Pendle-based yield protocol allows an attacker to drain approximately 11,109 ETH across Ethereum and Arbitrum.
• Synthetix launches SNAXChain — The derivatives liquidity protocol announces its own application-specific blockchain built on Optimism’s Superchain infrastructure, with governance council voting beginning September 6.
• Japan’s megabanks trial stablecoin cross-border payments — MUFG, SMBC, and Mizuho launch “Project Pax,” a stablecoin-based platform aimed at revolutionizing international transfers.
• DeFi market cap sits at $69.88 billion — Despite bearish price action, on-chain activity and protocol development continue to accelerate.
• Ethereum ETFs bleed $47.4 million in single-day outflows — The largest outflows since early August compound a difficult week for ETH investors.

Penpie Suffers $27 Million Reentrancy Exploit

The DeFi security conversation is once again at the forefront after Penpie, a yield generation protocol built on top of Pendle Finance, confirms a devastating exploit. On September 3, an attacker leverages a reentrancy vulnerability in Penpie’s PendleStakingBaseUpg.sol contract to inflate their reward balance and drain approximately $27.3 million worth of assets from the protocol. The stolen funds are quickly converted into 11,109 ETH and spread across Ethereum and Arbitrum networks.

Cybersecurity firm Cyvers reports that the attacker’s wallet is funded through a cryptocurrency mixing service, a common tactic used to obscure the origin of funds in exploit operations. The Penpie team’s monitoring system detects the attack almost immediately, but within an hour the hackers have already siphoned the full $27 million from the protocol.

In response, Pendle Finance — the underlying platform on which Penpie is built — takes swift emergency action by pausing its own contracts. This decisive move reportedly prevents an additional $105 million from being drained, a critical intervention that limits the total damage. Penpie files reports with the FBI and Singapore police, and the team begins working with blockchain security firms to trace the stolen funds.

The incident highlights a persistent weakness in the DeFi ecosystem: composability between protocols creates powerful financial instruments but also expands the attack surface. Penpie’s vulnerability stems from the absence of a reentrancy guard in a contract that handles permissionless market registration — a subtle but catastrophic oversight that auditing processes failed to catch. The hack pushes total crypto theft in 2024 past $1.2 billion, according to cybersecurity trackers.

Synthetix Announces SNAXChain on Optimism Superchain

While security concerns dominate headlines, one of DeFi’s oldest and most established protocols is making a bold infrastructure play. On September 4, Synthetix publishes a blog post detailing plans for SNAXChain, an application-specific blockchain built on Optimism’s Superchain infrastructure. The announcement signals a growing trend of major DeFi protocols moving beyond single-chain deployments to control their own execution environments.

SNAXChain joins a growing list of OP chains that includes Base, Lyra, Mode, and Zora. By building on Optimism’s technology stack, Synthetix gains access to shared security features and a unified communication layer while maintaining autonomy over its protocol’s performance and governance. The protocol partners with Conduit for chain infrastructure management and Wormhole for cross-chain messaging between SNAXChain, Optimism, and Ethereum mainnet.

The move addresses long-standing scalability challenges. As demand for synthetic assets grows, the limitations of operating solely on Ethereum’s base layer or individual L2 networks become increasingly apparent. SNAXChain is designed to serve as a neutral hub for on-chain governance and protocol decisions, while Synthetix simultaneously expands to additional blockchain networks and L2 solutions.

Governance council voting for SNAXChain begins on September 6, with interested nominees required to bridge a small amount of ETH to the new chain for gas fees before connecting their wallets to the Synthetix governance app. The governance overhaul represents a new chapter for the protocol, which has been a cornerstone of Ethereum DeFi since its launch in 2017.

Japan’s Megabanks Launch Project Pax Stablecoin Trial

Institutional adoption of stablecoin technology takes a significant step forward on September 6 as Japan’s three largest banks — Mitsubishi UFJ Financial Group (MUFG), Sumitomo Mitsui Banking Corporation (SMBC), and Mizuho — announce the trial phase of “Project Pax,” a stablecoin-based platform designed to streamline cross-border transactions.

The initiative, developed jointly by DLT platform Progmat along with Datachain and TOKI, enters its prototype phase with an ambitious goal: commercializing a stablecoin-powered cross-border payment platform by 2025. The project leverages Japan’s progressive stablecoin legislation, which came into effect in 2023, making Japan one of the first major economies to establish a clear regulatory framework for stablecoin issuance.

Project Pax represents a significant milestone for stablecoin adoption in traditional finance. Unlike crypto-native stablecoin projects, this initiative is backed by three of the world’s largest financial institutions, collectively holding trillions in assets. The banks plan to use stablecoins to reduce settlement times, lower transaction costs, and increase transparency in international transfers — areas where the traditional correspondent banking system has long struggled.

The trial is expected to explore various use cases for cross-border transfers, potentially including remittances, corporate payments, and trade finance. If successful, Project Pax could serve as a blueprint for other major banking consortia looking to integrate blockchain-based stablecoins into their existing infrastructure.

Broader DeFi Market Under Pressure

The protocol-level developments come against a backdrop of significant market stress. Bitcoin and Ethereum are both down more than 9% on the weekly chart as of September 6, driven by a combination of weak macroeconomic data and mounting expectations of Federal Reserve rate cuts. Ethereum ETFs experience $47.4 million in single-day outflows — the largest since early August — while Bitcoin ETFs see a combined $287.78 million withdrawn, the largest outflow since May 1.

Whale activity has also declined sharply. Bitcoin transactions exceeding $100,000 have fallen from approximately 115,000 during a peak in March to around 60,000 by the end of August. Ethereum’s high-value transactions show an even steeper decline, dropping from 115,000 to just over 31,000 in the same period. Analysts suggest this could indicate strategic accumulation by large holders positioning for a potential market recovery.

Despite the bearish price action, the total DeFi market cap remains at $69.88 billion, and protocol-level innovation continues at a rapid pace. Leading DEX Uniswap recently reached $50 million in cumulative total revenue, while Aave has seen a resurgence in interest from crypto whales. These fundamental indicators suggest that the DeFi sector’s long-term trajectory remains intact, even as short-term market conditions prove challenging.

Why This Matters

The events of September 6, 2024 illustrate the dual nature of DeFi’s current evolution. On one hand, the Penpie exploit serves as a stark reminder that security vulnerabilities remain a critical threat to the ecosystem’s credibility and user funds. The $27 million loss — and the near-miss of an additional $105 million — underscores the importance of rigorous smart contract auditing and the inherent risks of composability between DeFi protocols.

On the other hand, the Synthetix SNAXChain announcement and Japan’s Project Pax trial demonstrate that DeFi infrastructure is maturing at an unprecedented pace. Protocols are no longer content to operate as smart contracts on shared networks — they are building dedicated chain environments optimized for their specific use cases. Meanwhile, traditional financial institutions are moving from theory to practice with stablecoin integration, lending institutional credibility to the broader DeFi thesis.

For investors and builders in the space, the message is clear: DeFi is simultaneously becoming more sophisticated and more complex. The protocols that survive and thrive will be those that prioritize security alongside innovation, and that can bridge the gap between crypto-native users and the institutional capital waiting on the sidelines. The coming months — particularly as the Federal Reserve begins its expected rate-cutting cycle — will be a decisive period for the sector’s next growth phase.

Disclaimer: This article is for informational purposes only and does not constitute financial advice. Cryptocurrency investments carry significant risk, including the potential for total loss. Readers should conduct their own research and consult with a qualified financial advisor before making investment decisions. Past performance is not indicative of future results.