Description

MainStreet Bancshares (Nasdaq: MNSB & MNSBP), the parent company of MainStreet Bank, recently announced a data breach affecting some of its customers. The financial institution, based in Fairfax, Virginia, disclosed in a U.S. Securities and Exchange Commission filing that the incident originated with a third-party vendor and did not compromise the bank's internal systems. Upon discovering the breach, the Fairfax, Virginia-based institution immediately launched an investigation, enacted its incident response protocols, and terminated its partnership with the vendor. By April 28, the bank confirmed that the breach exposed personally identifiable information (PII) belonging to a segment of its customer base. However, MainStreet Bank emphasized that its own networks remained secure, with no evidence of unauthorized financial transactions or monetary losses. Customer accounts continued to operate normally, and no funds were transferred to unauthorized individuals. A letter sent to the Massachusetts Office of Consumer Affairs and Business Regulation indicated the breach was tied to a merchant's payment card system. The breach, which occurred between April 17, 2023, and April 22, 2025, involved payment card details, including cardholder names, card numbers, and expiration dates. Significantly, the bank stated that sensitive information, such as Social Security numbers or MainStreet Bank account numbers, was not impacted. MainStreet Bank, which operates six branches in Virginia and Washington, D.C., and offers access to approximately 55,000 ATMs, is advising affected customers to obtain replacement cards either by mail or in person. Customers are also encouraged to vigilantly review their account statements for any unusual activity.