Fireworks AI Notifies Customers of a Second Hack in Weeks

Tens of thousands of files holding customer data were exposed in an Oct. 24 breach of the cloud infrastructure Fireworks AI uses, the Nvidia- and AMD-backed startup told customers on Monday. It is the company's second known hack in a matter of weeks.

Fireworks said in a blog post that an unauthorized third party breached an external cloud provider that hosts the company's machines. The Oct. 24 incident included tens of thousands of files that contained customer data in some cases, according to a person familiar with the matter.

Fireworks helps other companies run artificial intelligence models, so customer data — including datasets and incomplete models, by its own description — sits in files the startup keeps on infrastructure it does not own outright. That distinction is where the latest incident landed.

What happened, in sequence?

• Early October: Fireworks AI discloses that unauthorized parties used internal Fireworks credentials to reach a number of customer accounts.
• Oct. 24: An external cloud provider hosting Fireworks machines is breached; tens of thousands of files are accessed, customer data in some cases.
• Monday: Fireworks confirms its investigation and says account and billing information were impacted, along with "secrets, datasets and incomplete models" for a limited set of accounts.

The sequence matters because the second breach arrived while the first was still being investigated. Plainly, the company had two security problems running at once.

What did the investigation turn up?

On Monday, Fireworks confirmed in the blog post that its inquiry into the early October breach uncovered impacts to customers' account and billing information. For a limited set of accounts, the inquiry found "secrets, datasets and incomplete models." The startup said evidence links a cybercriminal threat actor group to the early October incident.

Fireworks launched its investigation with support from the cybersecurity firm Palo Alto Networks Inc. and notified law enforcement, the startup said in a statement. "We take this matter very seriously and are connecting directly with customers to provide appropriate support," the company added.

Fireworks did not say whether the Oct. 24 cloud breach shares an actor with the October credential theft, or whether the credential abuse handed attackers the keys to the cloud provider. In plain terms, the company has described two intrusions and left the connection between them unstated.

Which customers were exposed, and what isn't known?

Fireworks counts more than 10,000 customers, including the legal technology firm Harvey, the productivity software company Notion and the coding company Cursor, according to its website. A company spokesperson said Fireworks is "actively working with our customers to manage the incident, including Notion, Cursor and others."

The company did not disclose how many of those 10,000-plus accounts were affected in either incident. It did not name the breached cloud provider, say whether the files were copied or only accessed, or publish a timeline for customer notice.

Tens of thousands of files is a modest haul against a customer base of more than 10,000 accounts, which suggests a targeted subset rather than a wholesale leak — though Fireworks has not confirmed that reading. Even so, "secrets" remains undefined, and the company did not say what those secrets contain.

Does the funding picture change the risk?

Fireworks' backers include Nvidia Corp. and Advanced Micro Devices Inc. The startup was last valued at $17.5 billion in July and is in discussions for a new round of funding at a valuation of between $30 billion and $40 billion, people familiar with the matter said.

That range means a 71% to 129% increase over the July valuation, and it arrives with both investigations still open. Investors are pricing demand for the infrastructure Fireworks rents out to run other companies' models; the security file riding alongside it has no disclosed resolution date.

Takeaway: at the top of that range, investors would be valuing Fireworks at more than twice its July price while the company still cannot say how much customer data was exposed or who broke in.

For the 10,000-plus customers, the practical questions are concrete: whether credentials still work, whether proprietary data was copied, and whether the two incidents are one story or two. Fireworks answered none of them in the post, and the next funding round may set the price before the forensics do.