Fireworks AI reports second breach as Oct. 24 cloud attack exposed customer files

What happened

Fireworks AI, a startup that helps businesses run AI models, alerted customers Monday that an unauthorized party compromised an external cloud host on Oct. 24. A person familiar with the matter said the intrusion involved tens of thousands of files, and some contained customer information.

This comes on the heels of a different issue in early October, when the company said internal Fireworks credentials were misused to reach a number of customer accounts. In a Monday update, Fireworks said the earlier breach affected account and billing records and, for a limited group, touched "secrets, datasets and incomplete models." The company said evidence ties a cybercriminal threat group to that early October incident. It has not identified who carried out the Oct. 24 breach.

Customers and the company response

Fireworks lists more than 10,000 customers on its site, including Harvey, Notion and Cursor. A spokesperson said the team is "actively working with our customers to manage the incident, including Notion, Cursor and others."

Upon detecting unauthorized access on certain systems, Fireworks brought in Palo Alto Networks Inc. to assist the investigation and alerted law enforcement. The company said it had also engaged a cybersecurity firm earlier in October "to assist with the incident," and added, "We take this matter very seriously and are connecting directly with customers to provide appropriate support."

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What it means for investors

Fireworks' investors include Nvidia Corp. and Advanced Micro Devices Inc. In July, the startup carried a $17.5 billion valuation, and people familiar with the discussions say it is now seeking new financing that might value it between $30 billion and $40 billion.

Why this matters: security posture is now a line item in AI infrastructure investing. Repeated incidents not only create operational risk, they can influence customer churn and valuation narratives. If you hold chipmakers or late-stage private tech exposure in your portfolio, keep an eye on how Fireworks manages remediation and disclosure, and whether customers like Notion and Cursor stay put or shift providers.

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