Why a bug that could have threatened XRP's 100 billion supply cap stayed hidden for years

A bug that could have let an attacker print new XRP (XRP) out of nothing sat in the XRP Ledger for more than a decade without anyone noticing because normal user activity never came close to triggering it, according to XRP Ledger Foundation.

The 11-year-old bug mattered because it threatened the core rule XRP holders rely on: that the total supply can never exceed the 100 billion coins created at the blockchain’s debut in 2012. It was uncovered Sept. 22 by researcher Cayden Liao and Veria AI and reported internally.

No damage was done, according to RippleX, which shipped the fix. No new XRP was created and about 99.986 billion XRP remain in circulation today, the foundation said.

The XRP Ledger (XRPL) is an open-source, decentralized layer-1 blockchain. Its native token, XRP, was built so that no new tokens can ever be minted. The coin is primarily used to pay transaction fees and bridge currency trades on the ledger's built-in decentralized exchange (DEX).

However, the bug, believed to have existed since 2015, provided a way around that, at least in theory.

Here’s how it could have worked

The bug stemmed from a vulnerability known as an “integer overflow,” which, like an old arcade game’s score counter, resets to zero every time it hits its maximum.