Cardano narrowly avoided a catastrophic failure after a malformed transaction caused a temporary chain split, triggering a wave of confusion, criticism, and concern across the blockchain community.
Key Takeaways
- A years-old bug exploited by an AI-generated command led to a temporary split in the Cardano network.
- Independent node operators responded quickly, voluntarily deploying patches to keep the chain running.
- The incident raised serious questions about Cardano’s governance, security, and resilience.
- Cardano’s founder and community figures acknowledged the mishap as both a warning and a learning opportunity.
What Happened?
On November 21, 2025, a malformed transaction triggered a chain split on the Cardano network. The disruption stemmed from an old bug dating back to 2022, which was unintentionally exploited by a stake pool operator (SPO) relying on AI-generated instructions. This caused nodes to diverge, creating two competing chains and threatening network stability until a swift patch resolved the issue.
Make sure to share it when the FUD comes rolling in pic.twitter.com/dt3WSVgYvO
— Charles Hoskinson (@IOHK_Charles) November 23, 2025
AI Mishap Ignites Cardano Chaos
The incident began when a Cardano SPO known as “Homer J” attempted to replicate a known transaction issue using AI-generated code. According to his own post on X, he mistakenly executed the commands on the mainnet instead of a testnet, leading to widespread consequences.
“I felt awful as soon as I realized the scale of what I caused. I am sorry, Cardano community,” Homer wrote, admitting the error was unintentional and without any financial motivation.
The malformed transaction caused a rare edge-case error in the node implementation, leading to a fork where some nodes accepted invalid data. This fractured the network briefly and disrupted core services including decentralized finance (DeFi) applications and block rewards.
Charles Hoskinson Calls It a Premeditated Attack
While Homer claimed the act was an unintentional mistake, Cardano founder Charles Hoskinson described the incident as a premeditated attack. He alleged that Homer had been active for months in a Discord community, targeting Hoskinson’s own staking pool and looking for ways to damage the brand of Input Output Global (IOG).
Hoskinson confirmed that:
- Stake pool operators lost rewards.
- Transactions risked double spending.
- The entire Cardano ecosystem was impacted.
He stressed that recovery would take time and damage to Cardano’s reputation could be lasting.
Community Response and Recovery
Despite the severity, the network did not shut down. Independent node operators detected the abnormal behavior early and coordinated through decentralized means to deploy an emergency software patch. These patched nodes formed consensus, allowing the valid chain to continue.
Intersect, a key Cardano ecosystem organization, confirmed that the chain split was temporary and Ouroboros consensus mechanisms functioned as intended, with valid nodes eventually outweighing the invalid ones.
The official fix, node version 10.5.3, was released to reject the malformed transaction and remerge the split chains. A working group was also formed to help reconcile data from both sides of the chain.
Governance and Security Concerns Surface
The incident cast a spotlight on governance transparency and security readiness within Cardano. Observers, including community member Krumlar, criticized the system’s fragility.
“What’s really bad is the fragile nature of Cardano, if it can be broken this easily,” he said, highlighting the ease with which a non-malicious actor could cause major disruption.
Others pointed to parallels with historical crypto failures, such as Bitcoin’s 2013 fork and Ethereum’s 2016 DAO hack, suggesting that no blockchain is immune to design limitations or human error.
CoinLaw’s Takeaway
In my experience covering crypto infrastructure, this Cardano episode is a sobering reminder that even the most academically rigorous protocols are vulnerable to the unpredictable mix of old code, new tools, and human curiosity. I found the community’s fast coordination impressive, but what really stands out is the need for more robust safeguards, especially as AI tools become more widely used by developers and operators alike. This wasn’t just a tech bug. It was a stress test of trust, and while Cardano survived, it must evolve to avoid future cracks.
