St. Mary's Credit Union Data Breach: Financial Data Exposed
By Join The Case · Published November 13, 2025 · Updated November 13, 2025 · 6 min read
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Dapeer Law, P.A., a top-rated class action law firm, is investigating the St. Mary's Credit Union data breach. If you received notice that your information was exposed during this breach, you may be entitled to compensation. It's free to join our investigation to see if we can help you recover.

St. Mary's Credit Union Data Breach Lawsuit Investigation

On November 12, 2025, St. Mary's Credit Union quietly disclosed a security incident that exposed debit-card information belonging to three members. If you received a breach notice, you may be entitled to compensation and complimentary legal guidance—contact our data-privacy team for a free case evaluation today.

Key Facts at a Glance

  • Breach revealed: November 12, 2025 (notice filed with the Massachusetts Attorney General)
  • Individuals affected: 3 Massachusetts members
  • Data involved: Debit-card number(s) tied to the affected accounts
  • Official document: Download Official Breach Notice (PDF)

What Happened?

Mastercard alerted St. Mary's Credit Union that a card ending in XXXX may have been compromised, allowing unauthorized access to associated funds. The credit union then notified impacted members and the Massachusetts Attorney General on November 12, 2025.

Information Exposed

The notice confirms exposure of the following data category:

  • Credit/Debit card numbers (specific card ending in XXXX)

How St. Mary's Credit Union Responded

According to the letter, the credit union implemented several safeguards to protect members:

  • Activated fraud-monitoring software to flag suspicious transactions
  • Temporarily lowered daily debit-card limits to $210 (ATM) and $500 (point-of-sale)
  • Issued replacement cards to impacted members, expected to arrive within two weeks
  • Scheduled deactivation of the affected cards by 11/24/2025

Steps You Can Take Right Now

The notice urges members to stay vigilant and outlines several consumer-protection rights under Massachusetts law:

  1. Closely monitor account activity and report unauthorized transactions immediately.
  2. Obtain a police report if you detect suspicious activity on any financial account or credit report.
  3. Contact the fraud departments of the three major credit-reporting agencies to review your credit file.
  4. Place a security freeze on your credit report to block new credit without your authorization.

Potential Legal Claims

Financial institutions are obligated to safeguard member data. When they fall short, affected consumers can pursue statutory and compensatory damages. Our investigation is assessing whether St. Mary's Credit Union implemented reasonable security measures prior to the breach. If you experienced fraudulent withdrawals, account fees, or time lost addressing the incident, you may qualify to join a case.

Free Case Review: Complete our online form or call our intake team to discuss your rights—there is no obligation or cost to you.

Company Overview

St. Mary's Credit Union (St. Mary's Credit Union) is a Massachusetts-based credit union offering consumer and business banking services.

  • Headquarters: 46 Lizotte Drive, Marlborough, MA, United States
  • Founded: 1913
  • Industry: Financial services
  • Employees: 116
  • Website: stmaryscu.org
  • Member Solutions Center: 866-585-SMCU (7628)
  • Social: Facebook | Instagram | LinkedIn

Frequently Asked Questions

I received a data breach letter from St. Mary's Credit Union — what should I do?

Follow the letter’s instructions: monitor your account, review your credit reports, consider placing a security freeze, and contact the credit union immediately if you see unauthorized activity. You can also request a free legal consultation about possible claims.

How do I submit a claim related to the St. Mary's Credit Union data breach?

Click the “Free Case Review” link on this page or call our intake line. Our attorneys will confirm eligibility and guide you through next steps—there are no out-of-pocket costs.

What information did the St. Mary's Credit Union breach expose?

The breach involved debit-card numbers linked to affected accounts, potentially allowing unauthorized fund access.

Did St. Mary's Credit Union offer credit monitoring?

The notice does not mention complimentary credit-monitoring services. Impacted members are advised to monitor accounts and may place a free security freeze.

How many people were affected by the St. Mary's Credit Union breach?

The credit union reported the incident to the Massachusetts Attorney General as impacting 3 members.

How can I get the official breach notice (PDF) for St. Mary's Credit Union?

You can download the notice directly from the Massachusetts Attorney General’s website using the button above or by clicking here.

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