FBI Investigates Cardano Network Split After Alleged "Premeditated Attack"

Cardano co-founder Charles Hoskinson has confirmed that the Federal Bureau of Investigation (FBI) has been contacted following a temporary network split on November 21, 2025. The incident, caused by a malformed transaction exploiting a software flaw, led to a divergence in the blockchain, prompting Hoskinson to label it a "premeditated attack" rather than an accidental break.

The network disruption occurred when a faulty delegation transaction passed validation on newer node versions, while older versions rejected it, causing the blockchain to temporarily split into two chains. While some initial reports suggested a full network halt, staking pool operators and Hoskinson clarified that block production continued, albeit on divergent paths. This event tested the resilience of the Cardano infrastructure.

Charles Hoskinson took to social media to address the situation, stating, "Cardano works so fast that we forked, fixed, and caught the guy all in one day. He was quite active in the Fake Fred discord. It was absolutely personal and now he's trying to walk it back because he knows the FBI is already involved." He accused a "disgruntled stake pool operator" of deliberately attempting to harm the brand and reputation of Input Output Global (IOG), the company behind Cardano.

An individual identified as "Homer J." on X later claimed responsibility for submitting the transaction, describing it as a "careless action" and a "personal challenge" to reproduce a bad transaction using AI-generated instructions. However, Hoskinson expressed skepticism regarding the apology, suggesting it came only after the perpetrator became aware of the FBI's involvement.

Developers from IOG and the Cardano Foundation swiftly deployed a patch, version 10.5.3, to merge the divergent chains and resolve the issue within hours. Despite the quick recovery, the incident reportedly impacted all Cardano users, with potential implications for block rewards and transaction processing, and led to a temporary decline of over 5.9% in the ADA token's price.

In the broader cryptocurrency market, Cardano maintains a significant position. While the recent incident highlighted vulnerabilities, its market capitalization remains higher than that of Zcash (ZEC) and Hyperliquid (HYPE). However, both Zcash, following a substantial rally, and Hyperliquid are emerging as strong contenders, with analysts closely watching their potential to challenge Cardano's standing in the coming year.