The Litecoin blockchain restored normal operations after a 13-block reorg reversed invalid transactions created by unpatched nodes.
The Litecoin blockchain returned to normal after a 13-block reorganization wiped out invalid transactions created by outdated nodes.
In a post on X on April 25, the Litecoin team said a “zero-day bug” let some nodes accept bad transactions, forcing the network to rewrite blocks 3,095,931 through 3,095,943. The fix played out over about 2 hours and 45 minutes.
The issue was tied to Litecoin’s MimbleWimble Extension Block, a privacy feature that handles transaction accounting.
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According to the Litecoin team, non-updated nodes “allowed an invalid MWEB transaction,” which enabled LTC▲$42.55 to be pegged out to third-party decentralized crypto exchanges. Updated nodes rejected that chain, and a competing valid chain eventually replaced it.
At the same time, a denial-of-service attack hit parts of the mining network. Data compiled by blockchain analytics firm ltc.supply shows block times slowed to about 12.7 minutes, roughly five times the usual 2.5-minute target.
Litecoin Blockchain Corrects Itself
Once enough updated miners were active, the valid chain overtook the invalid one. The network automatically reorganized, removing the 13 bad blocks entirely. The Litecoin team reassured that “all valid transactions during that period remain unaffected,” while invalid ones “will not be included in the main chain.”
Data by ltc.supply shows F2Pool mined all 13 blocks on the winning chain. Other pools, including AntPool and ViaBTC, produced none during that window, suggesting only part of the network was running updated software.
What’s Still Unclear
Some details still remain unclear. For instance, the Litecoin team hasn’t disclosed how much LTC was involved or which decentralized crypto exchanges were targeted.
There are also competing explanations. Alex Shevchenko, who leads Aurora Labs, a blockchain infrastructure firm, said on X the attacker may have known about the bug ahead of time and used a DoS attack to weaken updated miners.
Other analysts questioned whether the issue was truly a “zero-day” or a known vulnerability that hadn’t been fully patched across the network. None of those claims have been independently confirmed so far.
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