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Got a notice from MemberSource Credit Union? Here’s what to do.

MemberSource Credit Union told the Montana Attorney General that people’s information was exposed. If you got a letter, work through the steps below.

Your checklist

  1. 1

    Keep the letter

    Save the notice from MemberSource Credit Union and its envelope. The date you were told can matter for legal deadlines.

  2. 2

    Freeze your credit

    Your Social Security number is listed in the filing. A free freeze at Equifax, Experian and TransUnion stops new accounts being opened in your name.

  3. 3

    Call your bank

    Account or card information is listed. Ask your bank for a new card number and watch statements for small test charges.

  4. 4

    Get a free claim review

    Our legal team checks whether you can be paid for this breach. No fee unless you recover.

Step 4: free claim review

Tell us you got the MemberSource Credit Union notice. An attorney, not a call center, reads it and tells you plainly whether you have a claim.

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  • Reply within 24 hours

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About the MemberSource Credit Union breach

Reported to
Montana Attorney General
Date filed
May 5, 2026
People notified
Not stated
Cause in filing
Not stated

Information listed in the filing: Full Name, Social Security Number, Financial Account Number, Date of Birth, Routing Number, Credit Score Information, Transaction History, Mailing Address.

MemberSource Credit Union operates as a member-owned financial cooperative, providing essential banking services such as savings and checking accounts, mortgage loans, auto financing, and consumer credit lines to individuals and families. Because credit unions function as primary financial hubs for their members, they maintain deep repositories of highly sensitive personal and financial documentation. This institutional relationship requires members to entrust the credit union with comprehensive details about their personal lives, income streams, and everyday spending habits, turning these organizations into significant targets for cybercriminals seeking high-value financial data.

In 2026, MemberSource Credit Union reported a formal data security incident to the Montana Attorney General, alerting account holders to a breach of its digital network infrastructure. While specific technical disclosures continue to evolve, financial institution compromises of this magnitude typically involve sophisticated cyberattacks such as unauthorized database access, credential harvesting, or exploitation of vulnerable third-party vendor systems used for transaction processing and customer relationship management. These incidents frequently bypass perimeter defenses, allowing malicious actors to dwell undetected within internal networks and quietly exfiltrate massive volumes of confidential consumer records.

The exposure resulting from the MemberSource Credit Union breach compromises several categories of sensitive information, each carrying severe downstream risks for affected members. The compromise of full names, dates of birth, and Social Security numbers provides identity thieves with the core ingredients needed to open fraudulent credit lines, secure unauthorized loans, or commit government and tax fraud in the victim's name. Furthermore, the potential exposure of financial account numbers, routing details, and transaction histories directly threatens the security of members' liquid assets, paving the way for unauthorized wire transfers, fraudulent debits, and devastating account takeover schemes.

Financial institutions like MemberSource Credit Union are subject to stringent regulatory frameworks, most notably the Gramm-Leach-Bliley Act (GLBA) and applicable state data protection statutes, which mandate rigorous administrative, technical, and physical safeguards to protect nonpublic personal information. Under these legal standards, the credit union has an affirmative duty to maintain robust encryption, execute regular security audits, and promptly patch vulnerabilities across its digital ecosystem. The occurrence of a data breach strongly suggests a potential failure in fulfilling these statutory security obligations, raising serious questions about whether adequate protective measures were maintained prior to the incident.

For consumers who have received an official data breach notification letter from MemberSource Credit Union, this correspondence serves as legal confirmation that their private financial information has been compromised through corporate negligence. Legally, the receipt of this notice establishes the concrete injury and standing necessary to participate in a class action lawsuit aimed at holding the institution accountable for its security lapses. Affected individuals should know that participating in a class action requires no out-of-pocket costs, as our firm handles these matters strictly on a contingency fee basis, ensuring you pay nothing unless financial recovery is successfully secured on your behalf.

See the official filingFull ransomware checklist

MemberSource Credit Union data breach questions

How many people were affected by the MemberSource Credit Union data breach, and what was exposed?
The filing does not give a count of affected people and lists the following information as involved: Full Name, Social Security Number, Financial Account Number, Date of Birth, Routing Number, Credit Score Information, Transaction History, Mailing Address. Your own letter is the best guide to what was exposed about you, since notices are usually tailored to each person.
Is the MemberSource Credit Union data breach letter legit or a scam?
A notice from MemberSource Credit Union in the mail matches the breach MemberSource Credit Union reported to the Montana Attorney General on May 5, 2026. Check that the company name and dates in your letter match that filing. A real notice of data security incident won't ask for your password, Social Security number or a payment — if it does, contact MemberSource Credit Union through a phone number or website you find yourself.
Did MemberSource Credit Union offer free credit monitoring?
Any free monitoring MemberSource Credit Union is offering will be described in the notice you received, along with an activation code and a sign-up deadline. Because Social Security numbers are listed in this filing, identity monitoring and a credit freeze matter more than usual. Enrolling does not give up your right to bring a claim.
Is there a MemberSource Credit Union data breach class action lawsuit?
Law firms often open an investigation after a breach notice like this one, and a class action lawsuit may follow. This page doesn't confirm that a lawsuit has been filed against MemberSource Credit Union. You usually don't have to join a class action to be included — if a settlement is reached, class members are notified and can file a claim.
What should I do after getting the MemberSource Credit Union data breach notice?
Keep the letter and the envelope, and note the date it arrived. Freeze your credit with Equifax, Experian and TransUnion, change any passwords the notice mentions, and sign up for any free credit monitoring the letter offers. Then check whether you may have a claim.
Where can I see the official MemberSource Credit Union breach notice?
MemberSource Credit Union's report is published by the Montana Attorney General: https://dojmt.gov/office-of-consumer-protection/reported-data-breaches/#mt-membersource-credit-union-2026 Compare it with the letter you received to confirm the dates and details match.
Do I need a MemberSource Credit Union data breach lawyer or attorney?
An attorney can read your notice and tell you whether a claim makes sense. A case review here is free, and data breach cases are usually handled on contingency, so there is no upfront cost.
Can I sue MemberSource Credit Union over the data breach?
It depends on what was exposed, the law in Montana and your own state, and whether you've been harmed. Most people take part through a class action rather than suing alone. Keep your notification letter — it's the proof that connects you to the breach.
How much could a MemberSource Credit Union data breach settlement or claim be worth?
There is no set amount, and no MemberSource Credit Union settlement is confirmed here. In past data breach settlements, payments depended on what data was exposed and on documented losses — fraud, out-of-pocket costs and time spent dealing with the breach. The filing lists Full Name, Social Security Number, Financial Account Number as involved. Keep receipts and records; they're what damages claims are built on.

Other notices sent in Montana

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