Public breachBreachXposedOrNot· 1 Oct 2025
Substack
Domain: substack.com
What happened
Substack, a publishing and newsletter platform, suffered a data breach in October 2025 that was later circulated more widely in February 2026. The breach exposed 665k account holder records containing email addresses along with publicly visible profile information from Substack accounts, such as publication names and bios.
Breach facts
- Records exposed
- 665,183
- Sensitive
- No
- Industry
- News Media
- Data exposed
- Email addressesPhone numbers
This page summarises publicly reported breach metadata for awareness. For account recovery or incident response, use the official guidance from the affected service.
Breach data provided by XposedOrNot.