Cardano Experiences Temporary Network Split Due to Malformed Transaction

By Patricia Miller

Nov 22, 2025

2 min read

A malformed transaction caused a temporary chain split on Cardano's mainnet, but no user funds were compromised after emergency fixes.

How Did a Malformed Transaction Cause a Chain Split on Cardano?

A malformed transaction triggered a temporary split in the Cardano mainnet due to a vulnerability in a cryptographic library, which had its roots on the Preview testnet back in 2022. This incident, which occurred on November 20, resulted in a chain partition that separated the network into two distinct versions: one chain contained the problematic transaction while the other remained unaffected.

In response to this unexpected chain split, Cardano engineers promptly developed and released hotfixes and node upgrades. Stakeholders upgraded their nodes to version 10.5.3, effectively merging the two chains back into a single, functional network without compromising user funds.

What Actions Were Taken After the Incident?

The team conducted an investigation into the incident and identified the wallet associated with the malformed transaction. Preliminary forensics linked it to a participant from a previous Incentivized Testnet. Authorities, including the FBI, were notified to analyze the potential for a cyberattack due to the nature of the transaction.

Despite the challenges faced, Cardano's founder expressed relief that the network remained functional amid the crisis, highlighting the resilience and community spirit within the Cardano ecosystem.

Who Was Responsible for the Malformed Transaction?

In a twist to the situation, an individual on social media claimed responsibility for the malformed transaction. This admission sparked discussions within the community regarding the implications of such actions. The individual described the incident as an inadvertent fault resulting from a misguided experiment and offered an apology to the community for the disruption caused.

The response from Cardano's leadership pointed to the seriousness of the matter, emphasizing the swift actions taken against the perpetrator and indicating the involvement of law enforcement due to the event's implications. Overall, the Cardano network successfully navigated this challenge, reinforcing its infrastructure and highlighting the importance of ongoing vigilance in the blockchain space.

Important Notice And Disclaimer

This article does not provide any financial advice and is not a recommendation to deal in any securities or product. Investments may fall in value and an investor may lose some or all of their investment. Past performance is not an indicator of future performance.