Litecoin went through a serious network disruption Saturday after attackers reportedly exploited a bug tied to its MimbleWimble Extension Block, or MWEB, privacy layer.
Summary
Litecoin reversed 13 blocks after attackers exploited a zero-day bug in MWEB.
The attack opened a window for attempted double-spends against some cross-chain swap protocols.
The Litecoin Foundation said the bug has been patched, though some platforms reported losses.
According to the Foundation, the issue allowed some older mining nodes to accept an invalid MWEB transaction, creating a chain split that lasted more than three hours before the network restored the correct main chain.
13 Blocks Were Reversed
The incident affected blocks 3,095,930 through 3,095,943.
After the attack was identified, Litecoin went through a 13-block chain reorganization, wiping invalid transactions from chain history and restoring the valid chain.
The Foundation said legitimate transactions during that period were not affected.
But the reorganization created problems elsewhere.
Attackers reportedly used the fork window to try double-spend attacks through cross-chain swap protocols, where some MWEB peg-outs were accepted before later becoming invalid.
That is where losses may have happened.
Cross-Chain Protocols Took the Hit
Some damage appears tied less to Litecoin itself and more to connected protocols that trusted transactions during the fork.
Aurora Labs CEO Alex Shevchenko described it as a coordinated attack and said one protocol alone may have around $600,000 in exposure.
He also warned trading venues to review Litecoin deposits and balances because of multiple suspected double-spend attempts.
That has put attention back on risks tied to bridges and cross-chain systems when base-layer disruptions happen.
Bug Now Patched
The Litecoin Foundation said the vulnerability has now been fully patched.
It has not disclosed which mining pools were involved or how much fake value attackers tried to push through during the exploit.
The incident is notable because it is the first major known exploit involving MWEB since the privacy feature launched in 2022.
Bigger Questions for Litecoin
While the network recovered, the event raises fresh questions about security around privacy extensions and how older node versions can create vulnerabilities.
It also highlights how attacks do not have to break an entire blockchain to cause damage — exploiting edge cases around forks and connected protocols can be enough.
LTC traded near $56 after the news and was down modestly, but the bigger story may be what this means for confidence in cross-chain security and privacy-layer code going forward.
