HackingFinancial ServicesFinanceSkimmerCustomer Data InvolvedTargetedFinancial accountPIILowContained

MutualOne Bank

bd_c251b016573fad0a · schema v1 · pii pii-v1

Severity

Low

Discovered

May 9, 2026

Filed

May 20, 2026

To disclose

11 days

Affected

1state residents only

Confidence

66%

Full breach record for MutualOne Bank →438 incidents on file

MutualOne Bank reported a single-incident data compromise in Massachusetts affecting one resident. On May 7, 2026, a fraudulent debit card transaction occurred, likely via skimming or card-not-present fraud. The bank detected the incident on May 9, 2026, and notified the MA Office of Consumer Affairs on May 12, 2026. The bank credited the customer, deactivated the compromised card, issued a replacement, and advised the customer on fraud alerts and security freezes.

J jump to incidentP pin to compareR raw source

Massachusetts clock✓ MA AG ≤30d11 days discovery → filing

⚠ unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Incident timeline

undetected · 2 days

discovery → filing · 11 days

May 7, 2026

Begins

May 9, 2026

Discovered

May 20, 2026

Filed

vs. sector median

7 wks faster

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed1 affectedView incident

Name: MutualOne Bank
norm: mutualone bank
Domain: mutualone.com

Name: MutualOne Bank
norm: mutualone bank
Domain: mutualone.com
Industry: Financial Servicesllm

Discovered: May 9, 2026
Breach occurred: May 7, 2026
Undetected for: 2 daysoccurrence → discovery
Materiality determined: —
Notification sent: May 12, 2026
Affected individuals: 1state-resident count only
Data types: Financial accountPII
Attack vector: Unauthorized Access
MITRE ATT&CK: T1052 Exfiltration Over Physical Medium
Threat actor: ExternalFinancial
Regulator citations: Pursuant to M.G.L. c. 93H, we are writing to notify you of a possible data compromise
Initial access: external_remote_services

During the incident: Credited the above account for the following disputed transaction(s)
Fiserv Network has settled the transaction
Replacement debit card with a new card number has been made for you at the branch at no cost
Compromised card has been deactivated
Changes made: You should be mindful for the next 12 to 24 months in reviewing your account statements and notify us of any suspicious activity
Contact the fraud departments of the three major credit reporting agencies to discuss your options
Review your credit report and may obtain your report by contacting any of the credit reporting agencies
Place a free 90-day fraud alert on your credit file
Place a security freeze on your consumer credit report
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 11 days(11 days from discovery to filing)
Compliance flags: MA AG ≤30d
Discovery-date grounding: unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

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/2026-822-mutual-one-bank/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: May 20, 2026
Raw hash: 1840575b11cd484b447d0f0ddec0811e04f11d600b81d1578d9f4781608f72de

Reporting entityMutualOne Bank

Victim entityMutualOne Bank

Incidentdiscovered May 9, 2026

Stated responseCredited the above account for the following disputed transaction(s)

ComplianceMA AG ≤30d

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov