RetoSwap Suspends Trading Again: Haveno Protocol Exploit Twice

How the Haveno Protocol Exploit Drained $2.7 Million in XMR

The same vulnerability. The same target. The second attack in less than 30 days.

RetoSwap — the Monero-based peer-to-peer trading platform — has urgently suspended all trading again after announcing the Haveno trading protocol it runs on is being actively exploited. The team confirmed the suspension on June 17, 2026, raising the minimum client version to 2.0.0 and banning the attackers' onion addresses — the same emergency response used in the first attack on May 20, 2026.

Source: X(formerly Twitter)

RetoSwap has been clear on one point: its own infrastructure was not compromised. The vulnerability sits inside the Haveno protocol — the open-source trading framework that RetoSwap is built on. The team did not write the vulnerable code. They inherited it.

That distinction matters. It does not restore funds.

How the Haveno Protocol Exploit Drained $2.7 Million in XMR

To understand the June 17 suspension, you need the May 20 incident on record.

On May 20, 2026, Haveno lead developer woodser reported the Haveno trade protocol was actively being exploited. Within two minutes — at 2:33 UTC — RetoSwap banned the attacker's onion address and halted trading by setting the minimum client version to 2.0.0 using the filter feature.

The attack resulted in the theft of 7,000 XMR, valued at approximately $2.7 million. On-chain analyst PeckShield confirmed the breach.

The technical mechanism behind the exploit was sophisticated. The attacker sent a fake, out-of-order acknowledgment message impersonating the arbitrator — a neutral third party in Haveno's 2-of-3 multisignature wallet system. This caused the victim's client software to overwrite the legitimate arbitrator's node address with the hacker's own address. The victim's software then collected wallet keys including one from the attacker's fake arbitrator node. The hacker obtained 2 out of 3 wallet keys before the victim's funds were even deposited into the multisig wallet.

In plain English: the attacker posed as the referee before the game started — and rigged the outcome before any money entered the pot.

The impact primarily affected large cryptocurrency transactions. Fiat currency trading parties were not affected. That was not accidental. The attacker mapped the protocol's architecture, identified the specific pathway that handled large-volume crypto swaps, and targeted it precisely.

RetoSwap does not hold user funds. Traders operate directly from local wallets instead of depositing assets into a centralized account. But that non-custodial design provided no protection here — the exploit happened at the protocol layer, not at the platform layer.

RetoSwap Second Attack: What the Haveno Flaw Actually Did

The June 17 suspension confirms what the May 20 attack implied: the vulnerability was not fully resolved.

The fix applied after May 20 — mandatory upgrade to client version 2.0.0 and attacker address banning — stopped the active breach. The Haveno developer woodser identified the prevention as straightforward: check that the multisig wallet is already created before updating the arbitrator's address. A GitHub pull request was opened to address this. But the June 17 incident shows attackers found a way to exploit the protocol again — whether through a new vector or residual exposure in the same vulnerability.

RetoSwap confirmed on June 17 that losses appear limited to large crypto-asset transactions. Fiat traders were again unaffected. The team stated it is evaluating options to help affected traders recover and that trading will resume only after the protocol is fixed — this time with no timeline given.

Recovery options in the XMR ecosystem are largely a formality. Monero's privacy-first design — the same feature that makes it valuable — makes stolen XMR nearly impossible to trace or recover. PeckShield can flag the incident. The funds, once moved, are effectively gone.

This is the core tension of the entire story. The privacy that protects legitimate Monero users protects attackers equally well once the theft is complete.

What Haveno Protocol Users Must Do Right Now to Stay Safe

If you use RetoSwap or any platform built on Haveno, here are the verified steps from RetoSwap's own communications.

Step one — back up your wallet folder immediately. RetoSwap confirmed affected users will need their local wallet backup for any potential recovery plan. The folder locations are:

• Linux: ~/.local/share/Haveno-reto/xmr_mainnet/wallet

• macOS: ~/Library/Application Support/Haveno-reto/xmr_mainnet/wallet

Step two — do not attempt to trade until the protocol fix is confirmed. Trading remains suspended as of June 17, 2026. Any new trades attempted through a non-updated client risk exposure to the same multisig arbitrator spoofing attack.

Step three — update to client version 2.0.0 minimum before the platform reopens. RetoSwap set this as the minimum permitted version. Users running earlier versions should update before trading resumes.

Step four — verify arbitrator communications in any P2P trade. Always verify trade details and arbitrator communications in any P2P platform. Be cautious with platforms built on open-source protocols that have not undergone full independent security audits — the security of a forked project is only as strong as the least-audited code in its upstream dependency chain.

The broader lesson from both the May and June incidents is specific. RetoSwap did not write the vulnerable code. They inherited it — the way every forked project inherits the bugs, the blind spots, and the unaudited corners of whatever they built on top of. Users of any platform built on Haveno face the same inherited risk until the core protocol receives a complete independent audit.

Conclusion

The Haveno protocol has now been exploited twice in less than 30 days. RetoSwap's own infrastructure was not breached either time — but the protocol it depends on was. The May attack cost users 7,000 XMR worth $2.7 million. The June 17 suspension suggests attackers found the same door still open. Trading will resume when the protocol is fixed. Back up your wallet folder now. Do not trade until the fix is confirmed.

YMYL Disclaimer

This article is for informational and educational purposes only. It does not constitute financial, investment, or legal advice. All incident data is sourced from RetoSwap's official X account and verified public market sources as of June 17, 2026. The June 17 attack losses are still being assessed — figures may be updated as more information becomes available. All asset figures from the May incident are verified from multiple named sources. Always conduct your own independent research and consult a qualified security or financial advisor before using any decentralized trading platform.