Was your data in the Troy Hunt's Mailchimp List breach?
Check whether your email address was in it
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Troy Hunt's Mailchimp List (troyhunt.com) suffered a data breach in 2025 that exposed around 16,627 accounts. If you had an account, some of your personal data may be circulating in leaked databases. The fastest way to know is to check your own email — free, in about 30 seconds, no password required.
What happened
In March 2025, a phishing attack successfully gained access to Troy Hunt's Mailchimp account and automatically exported a list of people who had subscribed to the newsletter for his personal blog. The exported list contained 16k email addresses and other data automatically collected by Mailchimp including IP address and a derived latitude, longitude and time zone.
Breach record from Have I Been Pwned, CC BY 4.0. Risk analysis by Nullivo.
What was exposed, and why it matters
Not all breaches carry the same risk — what matters is which fields leaked. Here is what the Troy Hunt's Mailchimp List breach exposed and what each item actually enables:
Also listed in this breach: Email addresses, Geographic locations, IP addresses, Latitude and longitude pairs.
What to do if you were affected
These steps are ordered for this specific breach — the most urgent action given what leaked comes first.
- Location data
Review location sharing on the accounts you still hold with this service. - Email addresses
Treat any message referencing this service with suspicion, and never act on links in unexpected emails. - IP addresses
No direct action needed, but be wary of anyone quoting your location as “proof” of identity. - Confirm you were actually in it
Run a free scan before you spend time on the steps above.
How urgent is this now?
This breach is recent, so the data is actively traded and the risk is at its highest right now.
Remember: a breach can’t be “un-leaked” — once a database is out, it exists in countless copies. The goal is to make the leaked data useless: change what can be changed, lock down what can’t, and remove what has been republished.
Frequently asked questions
What data was exposed in the Troy Hunt's Mailchimp List breach?
The Troy Hunt's Mailchimp List breach exposed location data, email addresses, ip addresses. Reveals where you live, work or travel, which supports both targeted scams and physical-safety risks.
How many people were affected by the Troy Hunt's Mailchimp List breach?
Around 16,627 accounts were exposed, making it a smaller, more targeted breach.
What should I do if I had a Troy Hunt's Mailchimp List account?
Review location sharing on the accounts you still hold with this service. You can check whether your own email appears in this breach with a free Nullivo scan — no password required.
Breaches that exposed similar data
If the Troy Hunt's Mailchimp List breach affected you, these breaches exposed comparable information — worth checking too, since leaked datasets are routinely combined.