DataBreachInformation.com
See the full MemberSource Credit Union breach case facts
MonitoringMontanaFiled May 5, 2026

Understanding your MemberSource Credit Union data breach notification letter

If a MemberSource Credit Union letter arrived in your mailbox, here is what it means, why you received it, and the free steps you can take right now.

Why you received this letter

MemberSource Credit Union reported a data security incident to Montana regulators in May 2026, stemming from a breach that occurred in June 2025. The incident potentially exposed sensitive personal and financial information for an unspecified number of individuals, prompting vigilance from those affected.

Information the filing reports as involved

  • Full Name
  • Social Security Number
  • Financial Account Number
  • Date of Birth
  • Routing Number
  • Credit Score Information
  • Transaction History
  • Mailing Address

What to do after the letter

  1. Confirm the notice is genuine

    A legitimate MemberSource Credit Union notice references the specific incident reported to the Montana Attorney General and describes which categories of your information were involved. Compare the letter against the public filing before acting on any links or phone numbers it contains.

  2. Keep the letter — it is your proof of connection

    The notification letter is the document that ties your personal information to this incident. Keep the original and photograph it. If you later request a case review, this letter is the strongest evidence that you were among the affected individuals.

  3. Protect your accounts and credit

    Depending on what was exposed, consider a free credit freeze with all three bureaus, new passwords for reused credentials, and monitoring of financial statements. These steps are free and do not require you to wait for anyone's permission.

  4. Check the record against the public filing

    You can verify the MemberSource Credit Union incident against the filing reported to the Montana Attorney General. This registry summarizes what was filed; it does not provide legal advice.

This page summarizes a data breach reported to the Montana Attorney General for informational purposes. DataBreachInformation.com is a neutral reference registry and does not provide legal advice.

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