Cardano's blockchain faced a temporary chain split on November 22-23, 2025, triggered by an AI-related node bug, but recovered swiftly without halting transactions or losing funds. Solana co-founder Anatoly Yakovenko commended the network's proof-of-stake stability, highlighting the challenges of securing such systems without proof-of-work. The incident underscored a decade of formal methods in Cardano's engineering.
The chain split on Cardano occurred between November 22 and 23, 2025, affecting only a small portion of nodes that interpreted a malformed transaction differently due to an AI-related bug. The network resolved the issue rapidly through a standard node upgrade, ensuring no funds were lost and operations continued uninterrupted. Cardano founder Charles Hoskinson noted that the event demonstrated the protocol's strength, stating, "CARDANO SURVIVED WHAT MOST PROOF-OF-STAKE NETWORKS COULDN’T." He described the incident as a premeditated attack exploiting a specific edge case in consensus rules, which the network neutralized without hacks or disruptions.
Yakovenko, Solana's co-founder, publicly praised Cardano on social media, emphasizing the difficulty of building secure proof-of-stake systems without proof-of-work. He credited the recovery to a decade of formal methods and high-assurance engineering, saying the protocol "functioned as designed." This rare demonstration of operational continuity in a proof-of-stake chain maintained standard throughput, with minimal impact on exchanges and traders.
Cardano's Ouroboros consensus system and rigorous code testing proved effective in preventing lasting issues. Unlike most proof-of-stake networks that might require hard forks or checkpoints, Cardano avoided such measures entirely. The event boosted confidence in the network's stability.
Looking ahead, Cardano plans the Leios upgrade in 2026 to enable automatic and instantaneous recovery from similar events. Analysts view this as a benchmark for other proof-of-stake chains, offering lessons in early code verification and straightforward node fixes to maintain transaction integrity and prevent double-spending.