On November 21, 2025, Cardano (ADA) encountered a short-lived but notable chain split, caused by the exploitation of a long-standing code flaw through a deliberately malformed delegation transaction. This event led to a temporary division within the network, but engineers quickly addressed the issue, with
founder Charles Hoskinson commending the blockchain's robustness
in his remarks after the network was restored. The disruption was the result of a calculated attack orchestrated by a dissatisfied stake pool operator (SPO) who had spent months preparing for the exploit,
according to Hoskinson
, who referenced discussions in the Fake Fred Discord group as part of a larger scheme to undermine the network’s credibility.
The chain split took place when updated versions of the
Cardano
node software were unable to handle the malicious transaction, resulting in a fork between different node releases. Legacy nodes continued to validate blocks, allowing the network to function, though at a reduced speed. Stake pool operators acted quickly to upgrade to version 10.5.3, which restored stability to the network by the end of the day.
Hoskinson stressed that all funds were safe
and no blocks were lost, even though users experienced inconsistencies on the front end and slower transaction confirmations. The episode underscored the dangers posed by hidden vulnerabilities in blockchain systems, especially those that have gone unnoticed for extended periods, as this flaw had remained inactive until it was exploited.
The incident reignited discussions about Cardano’s governance and internal disagreements.
Hoskinson openly criticized the Cardano Foundation
(CF) for its approach to community oversight, leading to a dispute with CF community lead Nicolas Cerny over claims of “useful idiots” and reluctance to accept responsibility. Cerny responded by highlighting the foundation’s expanding responsibilities, including its support for DeFi and real-world applications, while Hoskinson advocated for organizational changes and new leadership at the CF. This public disagreement highlights persistent friction among Cardano’s founding organizations—IOHK, Emurgo, and the CF—regarding governance and strategic priorities, despite ongoing technical progress in the ecosystem.
The chain split also brought renewed attention to the security challenges facing decentralized networks.
Observers pointed out that Cardano’s architecture
helped limit the impact of the attack, but the event revealed the risk of targeted disruptions by insiders with specialized knowledge. Crypto analyst CryptoRus attributed the fork to a bug in the latest node software, noting that the network’s continuity was preserved by older nodes. At the same time, the attacker’s detailed planning—apparently informed by familiarity with IOHK’s processes—has led to calls for stronger security measures and greater community awareness.
As Cardano moves past the incident, the event stands as a warning for other blockchain initiatives.
Hoskinson’s recognition of the reputational impact
underscores the ongoing challenge of sustaining confidence in decentralized platforms. With
ADA
priced at $0.458 as of November 22, the community and investors are closely monitoring future governance changes and technical improvements within Cardano.