HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedData ExfiltratedFinancial accountPIILowContained

Main Street Bank

bd_261192707ae4ea56 · schema v1 · pii pii-v1

Severity

Low

Discovered

Jul 17, 2026

Filed

Jul 23, 2026

To disclose

—

Affected

Not disclosed

Confidence

65%

Full breach record for Main Street Bank →175 incidents on file

Main Street Bank notified Massachusetts customers of a suspected data compromise at a merchant's payment card environment. The incident, occurring between Nov 18, 2025 and July 6, 2026, exposed customer debit card numbers, names, and expiration dates. Bank systems were not compromised. Customers were offered new cards and advised to monitor accounts.

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Massachusetts clock✓ MA AG ≤30d

⚠ notification dateThe stored discovery date equals the NOTIFICATION date, collapsing the clock to ~zero. This UNDERSTATES the delay and can mask a real violation.

Incident timeline

undetected · 241 days

discovery → filing · 6 days

Nov 18, 2025

Begins

Jul 17, 2026

Discovered

Jul 23, 2026

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.ConfirmedView incident

Name: Main Street Bank
norm: main street bank

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

Discovered: Jul 17, 2026
Breach occurred: Nov 18, 2025 – Jul 6, 2026
Undetected for: 241 daysoccurrence → discovery
Materiality determined: —
Notification sent: Jul 17, 2026
Affected individuals: Not disclosed
Data types: Financial accountPII
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1041 Exfiltration Over C2 Channel
Threat actor: ExternalFinancial
Initial access: supply_chain

During the incident: Alerted customers via letter
Offered replacement debit cards
Recommended monitoring of account statements
Recommended placing fraud alerts on credit reports
Source: Quoted from the filing itself, not independently verified.

Compliance flags: MA AG ≤30d
Discovery-date grounding: notification dateThe stored discovery date equals the NOTIFICATION date, collapsing the clock to ~zero. This UNDERSTATES the delay and can mask a real violation.

Status: No extraction artifact recorded for this disclosure.

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/2026-1206-main-street-bank/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jul 23, 2026
Raw hash: a7d7512a868b5356e54fa5404fab52d371a15e0d5ad3f24f12908d4ef3f55660

Reporting entityMain Street Bank

Victim entityMain Street Bank

Incidentdiscovered Jul 17, 2026

Stated responseAlerted customers via letter

ComplianceMA AG ≤30d

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov