Summary

Substack, a popular newsletter platform, has informed its users of a data breach that occurred in October 2025, resulting in the theft of email addresses and phone numbers.

Key Points

• Substack experienced a data breach in October 2025.
• The breach involved the theft of user email addresses and phone numbers.
• Substack has begun notifying affected users about the breach.

Analysis

This breach highlights the ongoing risks associated with storing sensitive user information, such as email addresses and phone numbers. The exposure of such data can lead to phishing attacks and other forms of cyber exploitation. It is crucial for platforms handling user data to implement robust security measures to prevent unauthorized access.

Conclusion

IT professionals should ensure that sensitive user data is adequately protected through encryption and regular security audits. Additionally, users should be advised to remain vigilant for phishing attempts and to use multi-factor authentication where possible.