What changed

A bug that sat untouched in the XRP Ledger’s payment engine since 2015 could have let an attacker mint roughly 18 trillion spendable XRP in a single transaction, nearly 184 times the network’s entire 100 billion token supply, according to a vulnerability disclosure report cited by The Block. RippleX shipped a fix on Sept. 25, three days after the report came in, and did it by skipping the ledger’s usual two-week validator vote entirely, the first time that process has been bypassed in more than a decade.

Key Takeaways

  • An integer overflow in the XRP Ledger’s payment engine, present since 2015, could have let an attacker mint about 18 trillion spendable XRP in one transaction, according to the disclosure report.
  • Veria Labs, whose co-founder Cayden Liao said an AI agent found the flaw and built a working exploit, received the bug bounty program’s maximum $250,000 payout.
  • RippleX fixed the bug in xrpld 3.4.1 on Sept. 25, bypassing the normal amendment vote process for the first time in over 10 years because publishing the fix openly would have exposed the exploit for weeks.
  • Developers found no evidence the bug was ever exploited on a public network; source code for the fix was released roughly two weeks after the binaries, drawing criticism over XRPL’s claimed decentralization.

How the overflow actually worked

The flaw lived in how the payment engine totals what’s owed when a single payment sweeps through many order book offers at once, per CoinMarketCap. XRP balances are stored as 64-bit integers with a fixed ceiling, and the addition used to sum those offers had no overflow check. Push the sum past that ceiling and it wraps around to a small number instead of erroring out.

An attacker could exploit this by setting up a few hundred accounts, having each list a tiny fraction of some token for sale at an enormous XRP price, then closing every offer with one payment, according to The Block. Each seller wallet would be paid in full, while the buyer wallet would be charged only the wrapped-around total, described in the report as “only a few hundred drops plus the fee.” The difference is XRP that never should have existed.

Two safeguards should have caught this and didn’t, per CoinMarketCap. The ledger’s invariant check, built specifically to confirm no transaction creates new XRP, summed balance changes with the same unchecked arithmetic and wrapped identically. A separate check on single-account balances also missed it because the minted XRP could be spread thin across hundreds of accounts rather than concentrated in one. The disclosure report noted the exploit needed no significant starting capital, just a few hundred XRP in reserves (returned once the objects are removed) plus transaction fees. As the report put it, “the attack could not be triggered by accident. It required hundreds of offers priced in a way no real trader would use.”

Why the fix skipped the usual vote

Rule changes on the XRP Ledger normally go through an amendment process requiring support from more than 80% of trusted validators sustained over two weeks, so every server switches at the same moment. This fix instead took effect server by server as each one upgraded, a deliberate bypass the XRPL Foundation said was necessary because xrpld is open source and a standard release would have left the exploit visible in public code for weeks before activation, according to Cointelegraph. More than 80% of validators on the default Unique Node List had installed xrpld 3.4.1 by the end of Sept. 25.

That urgency collided with a separate decentralization debate. Source code for 3.4.1 was published roughly two weeks after the binaries went out, and Cyber Capital founder Justin Bons argued on X that running closed-source code for that stretch, paired with coordinated validator upgrades, undercut XRPL’s claim to be a fully decentralized public blockchain, a characterization central to arguments that XRP isn’t a security. The XRPL Foundation pushed back, saying the decision to bypass the amendment vote was made jointly by the Foundation, RippleX, core developers and validators, and that “no single party could make that call alone.” Independent validator operator XRP Kuwait made a similar point, telling Cointelegraph that “coordination is not the same as control.”

RippleX engineer Mayukha Vadari framed the withheld source code as a function of AI-era threat response rather than centralization, writing on X that “you can’t sneak a critical bug patch into a routine public release process, it’ll get spotted and reverse-engineered immediately.” RippleX Head of Engineering J. Ayo Akinyele said the team plans to expand AI-assisted bug hunting and formal verification going forward, calling AI “fundamentally changing how quickly vulnerabilities can be discovered.”

The find itself

Veria Labs co-founder Cayden Liao said the bug was surfaced by the firm’s AI agent, which also built a working exploit, and that Ripple paid Veria the bug bounty program’s maximum $250,000 award, per The Block. Liao said that, to Veria’s knowledge, it’s the largest payout ever made for a vulnerability discovered entirely by an AI agent. He attributed the decade-long miss to the fact that the flaw chained two separately low-severity bugs together: “we suspect one reason nobody caught this vulnerability is that it chains together two bugs that would be low severity on their own.”

The same xrpld 3.4.1 release also patched an unrelated bug in Batch, a feature that hadn’t yet gone live when the overflow was found. The Batch fix activated Friday alongside the rest of the release; per the report, an attacker exploiting it “does not gain anything on-chain,” with the risk instead being “a permanently malformed record and the chance to break off-chain indexers, explorers, and SDKs.” Servers still running older versions can no longer stay in sync with the network.

What to Watch

Developers said they found no evidence the overflow bug was ever exploited on a public network, so the immediate technical risk is closed. The open question is organizational: whether RippleX’s promised expansion of AI-assisted auditing and formal verification changes how future critical fixes get disclosed and shipped, and whether the decentralization debate sparked by the delayed source-code release resurfaces the next time an emergency patch bypasses the amendment vote.

Sources