An XRP Ledger amendment activated Nov. 4 strips a side effect from PaymentBurn, the permission issuers delegate so another account can burn their tokens, that in some cases let the delegate create new ones instead.
The amendment, fixCleanup3_4_0, was enabled at 14:52 UTC in ledger 108,112,129, according to amendment tracker XRPLWin. It shipped with xrpld 3.4.0, the server release that came out on Sept. 17.
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What the Flaw Allowed
Permission delegation lets one XRPL account hand specific powers to another. One of those powers, PaymentBurn, is meant to let a delegate destroy fungible tokens on an issuer’s behalf. The XRPL documentation says a delegate holding that permission “can also mint new fungible tokens” before the fix, covering trust line tokens and multi-purpose tokens (MPTs) “in certain circumstances.” Other granular permissions were not affected, and the native supply of XRP was not involved.
The fix itself is narrow. According to the xrpld 3.4.0 release notes, the ledger now rejects any PaymentBurn payment that crosses a zero balance. Until the amendment went live, the docs advised accounts not to delegate PaymentBurn at all.
The same amendment bundles other repairs, including rounding fixes for Single Asset Vaults, changes to AMM clawbacks, escrow reserve fixes and separate signing prefixes for counterparty and sponsor signatures.
Two Tries at Activation
XRPL amendments pass only when more than 80% of trusted validators back them for two straight weeks; a drop below that line restarts the count. XRPLWin data shows fixCleanup3_4_0 first reached a majority on Oct. 9 and lost it on Oct. 21, roughly 12 days into the window. Support came back the same day, and the second run held for the full 14 days.
Unchained reported on Oct. 9 that delegation had gone live on Oct. 8 while this fix was still short of the validator votes it needed.
The amendment is unrelated to the payment engine bug that could have broken XRP’s fixed supply. That integer overflow was patched in xrpld 3.4.1, released Sept. 25, with no validator amendment vote, according to the developers’ disclosure. The same report covered a second, lower-impact flaw in the Batch feature, fixed by the fixBatchV1_2 amendment that activated Oct. 9.
Why It Matters
For 27 days, delegation was live on mainnet while the burn permission could still create tokens, and the only safeguard was a line in the documentation asking issuers not to grant it. With the amendment enabled, issuers that want to hand burning duties to a separate account no longer have that caveat attached to the permission.
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