FEDERALItem 8.01 · voluntaryHackingFinancial ServicesFinanceData MishandlingSupply Chain (3P Vendor)Customer Data InvolvedPIIIdentity (basic)LowContained

MainStreet Bancshares, Inc.

bd_766723094ff84577 · schema v1 · pii pii-v1

Severity

Low

Discovered

Mar 1, 2025

Filed

May 30, 2025

To disclose

13 weeks

Affected

Not disclosed

Confidence

66%

Full breach record for MainStreet Bancshares, Inc. →

MainStreet Bancshares, Inc. (MNSB) disclosed a data security incident involving a core banking vendor. The vendor's system was compromised in March 2025, exposing PII of approximately 4.65% of MNSB's customer base. MNSB's own systems were not compromised. The company ceased the vendor relationship, notified regulators, and began notifying affected customers on May 26, 2025. MNSB does not anticipate material financial impact.

J jump to incidentP pin to compareR raw source

Incident timeline

discovery → filing · 13 weeks / 90 days

Mar 1, 2025

Discovered

May 30, 2025

Filed

vs. sector median

+5 wks slower

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

Name: MainStreet Bancshares, Inc.
norm: mainstreet bancshares
SEC CIK: 0001693577

Name: MainStreet Bancshares, Inc.
norm: mainstreet bancshares
SEC CIK: 0001693577
Industry: Financial Servicesllm

Discovered: Mar 1, 2025
Materiality determined: May 30, 2025
Notification sent: May 26, 2025
Affected individuals: Not disclosed
Data types: PIIIdentity (basic)
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1195 Supply Chain Compromise
Threat actor: External
Regulator citations: Notified appropriate regulators
Initial access: supply_chain

During the incident: Activated its incident response process
Ceased all activity with this provider
Notified appropriate regulators
Established appropriate monitoring systems
Notified impacted customers
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 13 weeks(90 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

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 filing

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

SEC 8-K / victim statementThis record

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

Source URL: https://www.sec.gov/Archives/edgar/data/1693577/000143774925019008/main20250328_8k.htm
DisclosureLens renders the full SEC/HHS filing inline below from the originating regulator’s public record (§4.5 fair report privilege).
Filed at: May 30, 2025
Raw hash: 44b91a1652a94c9976152a2ad13454b6bbcf4d2a020e4ead3173d66d03c8eb23

AI-assisted summary above. The structured extract on this page was generated from the document below. Inspect the source to verify or correct any field.

text/html29.5 KB

Download View at source

Reporting entityMainStreet Bancshares, Inc.

Victim entityMainStreet Bancshares, Inc.

Incidentdiscovered Mar 1, 2025

Stated responseActivated its incident response process

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.sec.gov

Source filing