HackingFinancial ServicesFinanceStolen CredentialsCustomer Data InvolvedIdentity (basic)Financial accountLowContained

MAINSTREET FEDERAL CREDIT UNION

bd_dc1bebca2267480f · schema v1 · pii pii-v1

Severity

Low

Discovered

—

Filed

Jun 18, 2026

To disclose

—

Affected

1state residents only

Linked

4 filings

Confidence

66%

Full breach record for MAINSTREET FEDERAL CREDIT UNION →

Mainstreet Credit Union notified the NH Attorney General that an unauthorized actor accessed an employee's email account between January 12 and January 20, 2026. The investigation determined that the account contained the name and financial account number of one New Hampshire resident. The organization secured the account, engaged a forensic firm, and mailed notifications to the affected individual on June 18, 2026.

J jump to incidentP pin to compareR raw source

Incident timeline

Jan 12, 2026

Begins

Jun 18, 2026

Filed

This filing is one of 4 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (3) · sorted by filing gap

Massachusetts State AGbd_8d3fdafae2c42fb42026-06-18Verified
Indiana State AGbd_95a5aa203651f1602026-05-04 · +45dCandidate
Nebraska State AGbd_a7b719418247207b2026-05-04 · +45dVerified

Name: MAINSTREET FEDERAL CREDIT UNION
norm: mainstreet federal credit union

Name: MAINSTREET FEDERAL CREDIT UNION
norm: mainstreet federal credit union
Industry: Financial Servicesllm

Discovered: —
Breach occurred: Jan 12, 2026 – Jan 20, 2026
Materiality determined: —
Notification sent: Jun 18, 2026
Affected individuals: 1state-resident count only
Data types: Identity (basic)Financial account
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1114 Email Collection
Threat actor: External
Regulator citations: Notified the New Hampshire Attorney General

During the incident: Instituted their incident response procedure
Secured the account
Engaged a forensic firm to assist
Searched and reviewed all the emails and attachments that were stored in the account for any personal information
Mailed a notification letter to the New Hampshire resident via U.S. First-Class mail
Changes made: Continue to assess its security procedures and training
Enhance the security of its email environment
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 · 4 filings · 4 states

View merged incident ↗

Indiana State AGMay 4 · first

Nebraska State AGMay 4 · first

Massachusetts State AG+45d

New Hampshire State AG+45d · this page

Pattern: first filing May 4 (IN), last Jun 18 (NH) — a 45-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://mm.nh.gov/files/uploads/doj/remote-docs/mainstreet-credit-union-20260618.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 18, 2026
Raw hash: cb214370f428906e4a0a646c288a2ee65a45a5c464a755c4587b0e64e7defac6

Linked disclosures

Regulatory filings (3) · sorted by filing gap

Reporting entityMAINSTREET FEDERAL CREDIT UNION

Victim entityMAINSTREET FEDERAL CREDIT UNION

IncidentUnauthorized Access

Stated responseInstituted their incident response procedure

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov