HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedFinancial accountIdentity (basic)LowContained

Main Street Bank

bd_62b3b67b80247add · schema v1 · pii pii-v1

Severity

Low

Discovered

—

Filed

Jun 16, 2026

To disclose

—

Affected

Not disclosed

Linked

2 filings

Confidence

66%

Full breach record for Main Street Bank →208 incidents on file

Main Street Bank notified Massachusetts customers of a suspected data compromise affecting a merchant's payment card environment. The incident, occurring between July 27, 2025, and March 31, 2026, potentially exposed debit card names, numbers, and expiration dates. Bank systems were not compromised; the breach originated from a third-party merchant. No SSNs or bank account numbers were accessed. Customers were advised to monitor statements and offered new debit cards.

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Incident timeline

Jul 27, 2025

Begins

Jun 16, 2026

Filed

This filing is one of 2 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (1) · sorted by filing gap

Massachusetts State AGbd_8d23ad6c7a9dc6d32026-08-13 · +58dCandidate

Name: Main Street Bank
norm: main street bank

Name: Main Street Bank
norm: main street bank
Industry: Financial Servicesllm

Discovered: —
Breach occurred: Jul 27, 2025 – Mar 31, 2026
Materiality determined: —
Notification sent: Jun 11, 2026
Affected individuals: Not disclosed
Data types: Financial accountIdentity (basic)
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Initial access: trusted_relationship

During the incident: Offered customers the option to visit a branch for an Instant Issued card
Offered to mail new MSB debit cards in 10-12 business days
Advised customers to monitor account statements for suspicious activity
Advised customers to use Internet Banking to monitor account activity
Advised customers to contact credit reporting agencies to place fraud alerts or security freezes
Source: Quoted from the filing itself, not independently verified.

Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 2 filings

View merged incident ↗

Massachusetts State AGJun 16 · first · this page

Massachusetts State AG+58d

Pattern: first filing Jun 16 (MA), last Aug 13 (MA) — a 58-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://www.mass.gov/doc/2026-983-main-street-bank/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 16, 2026
Raw hash: a4c2564ab2d0d54b8bc97648cd5979598fad4d0c69f29cd28e6c2a2306ccd6b0

Linked disclosures

Regulatory filings (1) · sorted by filing gap

Reporting entityMain Street Bank

Victim entityMain Street Bank

IncidentThird-Party / Supply Chain

Stated responseOffered customers the option to visit a branch for an Instant Issued card

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov