AI Tool Spots Key XRP Ledger Bug That Could Drain Wallets

A critical XRP Ledger bug in the signature-validation logic of an upcoming Batch amendment was caught by an autonomous AI security tool before reaching mainnet, according to a disclosure published Thursday by XRPL Labs. The flaw would have let an attacker siphon funds from any wallet without the owner's private keys. Because the amendment was still in its validator voting phase, no funds were ever at risk.

How the XRP Ledger Bug Worked

The Batch amendment was designed to let users bundle multiple operations into one transaction. Since individual operations inside a batch do not carry their own signatures, the system relies on a list of batch signers to verify that every involved account has authorized the bundle.

A loop error in the validation function created the exploit path. If it encountered a signer whose account did not yet exist on the ledger -- and whose signing key matched their own account, the default for any brand-new account -- it immediately declared the entire check successful and stopped verifying the rest of the list.

An attacker could exploit this by constructing a batch with three transactions: the first creates a new account the attacker controls, the second is a routine operation from that account making it a required signer, and the third moves funds from the victim's account to the attacker. The new account does not exist when validation runs, so the signer check exits early and never verifies the victim's authorization.

How Did Cantina AI's Apex Tool Find the Flaw?

Pranamya Keshkamat and Cantina AI's autonomous security tool Apex identified the vulnerability through static analysis of the XRP Ledger codebase on February 19, according to the disclosure. The team filed a responsible disclosure with Ripple's engineering division, which validated the report that same evening by building an independent proof-of-concept exploit.

The find highlights that AI-driven code auditing can catch subtle logic errors -- such as premature loop exits -- that human reviewers might miss. XRPL Labs said it would adopt AI-assisted code audit pipelines as a standard part of its review process going forward.

Ripple's Emergency Response

Ripple acted swiftly once the flaw was confirmed. Validators on the XRP Ledger's Unique Node List were immediately advised to vote against the Batch amendment. An emergency release, rippled 3.1.1, was published on February 23, marking both the Batch and the related fixBatchInnerSigs amendments as unsupported to permanently block activation.

A corrected replacement called BatchV1_1 has been built and is under review, with no release date set. The turnaround -- disclosure on February 19, patch out four days later -- reflects how seriously Ripple and the validator community treated the vulnerability.

What Does This Mean for XRP Ledger Security?

The episode signals a broader shift toward AI-powered security auditing in the blockchain industry. The exploit path was severe enough that activation would have compromised every account on the network, yet an autonomous tool flagged it before any human reviewer did.

XRPL Labs confirmed that expanded static analysis targeting premature loop exits and similar control-flow bugs will become standard practice for all future amendment proposals on the XRP Ledger.