An overflow flaw dating to 2015
An XRP bug in the Ledger's payment engine could have let an attacker create and spend XRP without paying for it. The integer-overflow vulnerability sat in the code since 2015. RippleX said it found no evidence anyone exploited the XRP bug on any public network.
Veria Labs, an AI security startup, reported the flaw through the bug bounty program on September 22, 2026. Researcher Cayden Liao said an AI agent found the XRP bug and built a working proof of concept entirely on its own.
The Ledger caps XRP supply at 100 billion tokens. Liao estimated one exploit transaction could have created roughly 18 trillion XRP, about 184 times the total supply. Recent exchange flows show XRP deposits far exceeding withdrawals, but the bug disclosure had no visible impact on those patterns.
How the attack worked
The XRP Ledger includes a built-in decentralized exchange where accounts post offers to swap one token for another. An attacker could open hundreds of accounts, each offering a tiny fraction of a token in exchange for a large amount of XRP.
A single payment would fill all those offers at once. The payment engine totaled the XRP amounts owed to sellers without an overflow check. When the sum grew too large, the counter wrapped around to a small number.
Sellers were paid in full. The buyer was charged almost nothing, just a few hundred drops plus transaction fees.
The Ledger's post-transaction safety check for newly created XRP relied on the same miscounted total. It missed the discrepancy. RippleX engineers reproduced the attack on a standalone server and confirmed the minted XRP could be spent in later transactions.
Emergency patch bypassed normal governance
RippleX shipped the fix in xrpld version 3.4.1 on September 25, three days after receiving the report. The patch took effect as each validator upgraded their server. More than 80 percent of validators on the default Unique Node List were running the patched version within hours of release.
This bypassed the XRP Ledger's standard amendment process, which normally requires over 80 percent of trusted validators to support a change for about two weeks before activation. XRP Ledger upgrades typically face delays when validator participation lags.
RippleX said a public vote would have exposed the XRP bug in open source code while it remained exploitable. The team called this the first time a transaction-processing change had deliberately shipped this way in more than 10 years of amendments.
The binary was released first. Source code was published roughly two weeks later.
Closed-source controversy and community reaction
Cyber Capital founder Justin Bons criticized the approach on October 8, saying XRP had been running closed-source code for two weeks. RippleX engineer Mayukha Vadari responded that critical bug patches cannot be disclosed in routine public releases.
The disclosure report was published on xrpl.org on October 9. It stated that the XRPL Foundation, RippleX, and validators made the decision together. RippleX confirmed that votes remain the standard for future changes.
Ripple paid Veria the bug bounty program's maximum reward of $250,000. Liao said this is the largest bounty ever paid for a vulnerability discovered entirely by an AI agent. RippleX Head of Engineering J. Ayo Akinyele wrote on October 10 that AI is fundamentally changing how quickly vulnerabilities can be found, and the team would expand AI-assisted bug hunting and formal verification.
Liao said he suspects one reason the flaw went unnoticed for so long is that it chained two bugs together, each of which would have been low severity on its own. Complex vulnerabilities have caught developers off guard before, as patches themselves sometimes introduce new attack vectors.
The 3.4.1 release also included a fix for a separate bug in the experimental Batch feature. That feature and its patch activated on October 9. Servers running older versions can no longer synchronize with the network.