Lightning Network developers fix critical bug that caused node downtime

Developers of Bitcoin's Lightning Network have issued a fix for a critical bug that led to downtime for some nodes.

The fix came after a user, identified as Bitmatrix founder Burak Keceli, made a large 998-of-999 multi-signature Taproot transaction — one that required 998 private key signatures to send the bitcoin. This was an abnormally large number of signers, and Lightning nodes failed to support the multisig transaction of that size.

Lightning Labs said the transaction triggered a series of events that completely disrupted the ability for nodes on the network to sync with each other, though it did not result in a loss of funds. As soon as the transaction was made, the network’s nodes rejected the specific block that included it, as well as subsequent blocks that came after it.

Keceli made the same kind of transaction last month, causing similar issues for the network — although due to a slightly different bug.

Keceli knew in advance their transaction would disrupt the network. Rather than disclosing the security bug in a responsible disclosure practice called CVE, short for Common Vulnerabilities and Exposures, Keceli proceeded to make the transaction anyway. He defended his actions, claiming the act was for the “ultimate good.”

"As a Bitcoin wizard, I summoned chaos theory in the name of darkness for the latter good," said Keceli in a tweet. "Responsible CVE is weaker magic," he added.

The Lightning Network is a Layer 2 network designed to get around Bitcoin’s slow transaction speeds and high fees. Users can port bitcoin to Lightning and transact with each other via payment channels at a significantly cheaper price than on the main network. Currently, there is 5,000 bitcoin ($100 million) locked in payment channels, per data from The Block.