Hoskinson: Cardano chain split was a deliberate attack, not a bug

Stakes over the recent Cardano network split have risen further, with founder Charles Hoskinson calling it a deliberate, targeted attack.
Summary

• Cardano split was not just a bug, says founder Charles Hoskinson
• The attack was targeted directly at himself, Hoskinson claimed
• He called it sabotage of critical infrastructure, and called the authorities

A malformed transaction that triggered a chain split on the Cardano network might not have been just a bug. On Monday, November 24, Cardano founder Charles Hoskinson called the incident an intentional exploit by a known individual inside the ecosystem.

The Cardano attacker doxed himself, left forensics evidence, had a history of malicious intent, breaking many laws in the process on this public infrastructure hack. #Cardano @IOHK_Charles pic.twitter.com/ZZj2RHEJik — St₳ke with Pride 🌈 SPO & DRep (@StakeWithPride) November 23, 2025

Hoskinson claimed that the malformed transaction that triggered a temporary fork was the work of a former stake pool operator (SPO) and early contributor.

He says the person used knowledge from Cardano’s (ADA) testnet days to craft a transaction that would disrupt block production and exploit validation inconsistencies across node versions.

“It was a targeted attack. Premeditated. It probably took several hours to figure out how to do it… It was a malicious act,” Hoskinson said.

Cardano attack—personal?

The incident, which occurred on November 21, involved a malformed delegation transaction. This caused a temporary split, with different Cardano node versions validating transactions differently.

According to Hoskinson, this was a “devastating attack,” which could have caused billions in damage on a bigger network.

“So if you go disrupt an electric grid or the internet or you do a cyberattack on… that’s a severe crime.” And so this is a public infrastructure that’s in more than 100 countries with millions of users around the world, and people’s livelihoods are connected to this," Hoskinson stated.

The attack targeted Hoskinson’s own pool, leading the founder to suggest the intent was personal. Hoskinson also said that he referred the case to law enforcement, including U.S. federal authorities.

“So when you maliciously attack a network thinking it’s going to be fun to damage my reputation, the collateral damage is every single user of Cardano,” he added.