Cardano Split in Half? Developer Says “Accident,” Hoskinson Says “Attack”
Cardano endured one of the most disruptive events in its history when a deliberately formed transaction triggered a chain split across the $14 billion network — the first such incident since the blockchain launched in 2017.
The exploit targeted a three-year-old bug within Cardano node software, allowing a malformed delegation transaction to bypass validation on newer node versions while being rejected by older ones.
According to an incident report from Intersect, the Cardano ecosystem governance organization, the result was two competing chains coexisting on the mainnet. The timing raised immediate concerns: the same anomaly occurred on Cardano’s testnet just 24 hours earlier, suggesting the exploit was tested ahead of its mainnet execution.
Although Cardano did not halt, Intersect emphasized that “block production continued on both chains throughout the incident, and at least some identical transactions appeared on both chains.”
The continuation of block production was cold comfort to users, however, as the two diverging ledger states created confusion across nearly every ecosystem touchpoint.
Exchanges Pause Operations as Network Data Becomes Unreliable
Major exchanges reacted swiftly to the chain split, suspending ADA deposits and withdrawals while monitoring which chain would achieve consensus dominance. Coinbase imposed the longest halt, pausing operations for roughly 14 hours from 12:15 UTC on Nov. 21 to 02:10 UTC on Nov. 22.
Other exchanges, including Upbit and Kraken, initiated shorter pauses as they validated ledger integrity, temporarily freezing liquidity for millions of ADA traders.
Block explorers struggled to interpret the fractured network, in some cases freezing or displaying contradictory data. DeFi protocols fared no better: smart contracts executed on one chain while associated transactions sometimes landed on the other. As a result, settlement times — typically measured in seconds on Cardano — ballooned to several minutes, while many transactions failed outright.
Behind the scenes, emergency coordination unfolded rapidly among Input Output Global (IOG), the Cardano Foundation, Intersect, and EMURGO. Developers shipped patch releases within three hours of diagnosing the bug, and by Nov. 22 the network naturally reconverged through consensus.
Even so, ADA’s price dropped as much as 16% during the turbulence before stabilizing near $0.41.
ADA price (Source: CoinGecko)
Developer Confesses as Hoskinson Calls the Incident a “Premeditated Attack”
Within hours of the disruption, an X user who goes by “Homer J” publicly claimed responsibility for the transaction that triggered the split. In a candid apology, the developer characterized the act as a poorly considered personal experiment that spiraled out of control.
“It started off as a ‘let’s see if I can reproduce the bad transaction’ personal challenge,” the developer wrote. They admitted relying on AI-generated instructions to firewall their Linux server without proper testing. “I’m ashamed of my carelessness and take full responsibility for it.”
But Cardano founder Charles Hoskinson rejected that explanation, calling the incident a “premeditated attack.” In a widely circulated X post, Hoskinson alleged that the developer tested the exploit on testnet and then deployed it knowingly on mainnet — adding that the FBI has already been notified.
A fact sheet distributed by Intersect echoed those remarks, stating that “relevant authorities and law enforcement are being notified.”
IOG Developer Resigns Amid Legal Concerns
Hoskinson’s decision to involve federal authorities has already triggered fallout inside Cardano’s core development organization. Roman — an IOG Plutus language engineer known online as “effectfully” — announced his resignation shortly after Hoskinson’s post.
Roman stated he had previously made mistakes during simulated cyberattack exercises and now feared that typical developer errors could expose team members to legal jeopardy. “I didn’t realize there was a risk of getting raided by the authorities because of that + saying mean things on the Internet,” he wrote.
The developer added that many vulnerabilities uncovered in Cardano’s computational layer were either discovered by him or derived from his research, underscoring his long-standing importance to the project.
As the network stabilizes, questions remain about governance, coordination, and how a years-old bug escaped detection — as well as the potential chilling effect Hoskinson’s response may have on future contributors. Cardano now faces not only a technical reckoning, but a cultural one.
