HackingFinancial ServicesFinanceData MishandlingSupply Chain (3P Vendor)Customer Data InvolvedIdentity (basic)Government IDFinancial accountMediumContained

M&T BANK CORPORATION

bd_72e6cad186791aba · schema v1 · pii pii-v1

Severity

Medium

Discovered

—

Filed

Apr 17, 2026

To disclose

—

Affected

Not disclosed

Linked

2 filings

Confidence

67%

Full breach record for M&T BANK CORPORATION →13 incidents on file

M&T Bank notified Nebraska residents of a data breach involving a third-party service provider in August 2025. Customer personal information, potentially including SSNs and financial account numbers, was accessed. M&T confirmed its systems were not affected and that the provider removed the data. The bank is offering 24 months of free credit monitoring via Equifax and advising customers to monitor accounts.

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Incident timeline — partial

? — ?

Breach window unknown

Apr 17, 2026

Filed

—

Corroborated · see linked filings

Compliance clocks stay unassessable until a regulatory filing lands. Dashed segments fill in automatically when corroboration arrives.

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_476c2c623aefc0972026-04-17Candidate

Name: M&T BANK CORPORATION
norm: m t bank
Domain: mtb.com

Name: M&T BANK CORPORATION
norm: m t bank
Domain: mtb.com
Industry: Financial Servicesllm

Discovered: —
Materiality determined: —
Notification sent: Apr 17, 2026
Affected individuals: Not disclosed
Data types: Identity (basic)Government IDFinancial account
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1195 Supply Chain Compromise
Threat actor: External
Initial access: supply_chain

During the incident: Began a comprehensive review
Worked closely with the provider to assess the situation
Confirmed that the service provider has securely removed your data from its systems
Continue to closely monitor your accounts for potentially fraudulent activity
Offering credit monitoring services from Equifax
Changes made: Offering credit monitoring services from Equifax for 24 months
Encouraged customers to review bank transactions and statements regularly
Provided resources on how to check credit reports and place fraud alerts
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 · 2 states

View merged incident ↗

Massachusetts State AGApr 17 · first

Nebraska State AGApr 17 · first · this page

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://nebraska.gov/ago/data-breach/documents/0f2a73f4-4e0c-46bc-8b88-75561ecdc7da.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Apr 17, 2026
Raw hash: b7c8cd4d73318e32c877c8824a0fadbe0c66bb58e7dbb3078752973148095f17

Linked disclosures

Regulatory filings (1) · sorted by filing gap

Reporting entityM&T BANK CORPORATION

Victim entityM&T BANK CORPORATION

IncidentThird-Party / Supply Chain

Stated responseBegan a comprehensive review

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancenebraska.gov