HackingProfessional ServicesProfessional ServicesData ExfiltratedCustomer Data InvolvedIdentity (basic)MinorMediumContained

CornerStone Staffing Solutions, Inc.

bd_8bd7efdaf1859fe9 · schema v1 · pii pii-v2

Severity

Medium

Discovered

Nov 17, 2025

Filed

Sep 18, 2026

To disclose

44 weeks

Affected

45state residents only

Linked

10 records

Confidence

67%

Full breach record for CornerStone Staffing Solutions, Inc. →

Cornerstone Staffing Solutions, Inc. detected anomalous activity on November 17, 2025, indicating unauthorized access to its systems between November 6 and 21, 2025. The investigation found evidence that data may have been exfiltrated, though the precise extent is uncertain. The incident affected 45 New Hampshire residents, including minors, whose personal information (names and other data) was present on the affected systems. Cornerstone engaged a third-party cybersecurity firm, contained the threat, and notified affected individuals starting September 11, 2026. The company is offering 12 months of complimentary credit monitoring and has implemented additional security measures.

J jump to incidentP pin to compareR raw source

Leak gap clock✗ Leak >180d44 weeks discovery → filing

Incident timeline

undetected · 11 days

discovery → filing · 44 weeks / 305 days

Nov 6, 2025

Begins

Nov 17, 2025

Discovered

Sep 18, 2026

Filed

vs. sector median

+24 wks slower

This filing is one of 10 records about the same incident.View merged incident

A leak claim by qilin about this victim was first seen 309 days before this filing.View originating leak claim

Linked disclosures

Why this link?

Ransomware claims (1)

Leak Siteqilinbd_ec840b7d9ffbec102025-11-13 · +309dVerified by operator

Regulatory filings (8) · sorted by filing gap

Texas State AGbd_d3cf7d86357026862026-09-15 · +3dVerified by operator
Vermont State AGbd_29de5dbb97b766ee2026-09-12 · +6dVerified
Iowa State AGbd_7eea8c1a8a079a322026-09-11 · +7dVerified
Oregon State AGbd_9b87af94259300b82026-09-11 · +7dVerified

Show 4 more filings ↓up to 17d gap

Washington State AGbd_a19802f40428b48c2026-09-11 · +7dVerified
Indiana State AGbd_d23a943331b636382026-09-11 · +7dVerified
California State AGbd_e4dfd8c0234818a12026-09-11 · +7dVerified
Massachusetts State AGbd_22dd62acb7c5bd852026-09-01 · +17dVerified

Name: CornerStone Staffing Solutions, Inc.
norm: cornerstone staffing
Domain: cornerstone-staffing.com

Name: CornerStone Staffing Solutions, Inc.
norm: cornerstone staffing
Domain: cornerstone-staffing.com
Industry: Professional Servicesllm

Discovered: Nov 17, 2025
Breach occurred: Nov 6, 2025 – Nov 21, 2025
Undetected for: 11 daysoccurrence → discovery
Materiality determined: —
Notification sent: Sep 11, 2026
Affected individuals: 45state-resident count only
Data types: Identity (basic)Minor
Attack vector: Unknown
MITRE ATT&CK: T1041 Exfiltration Over C2 Channel
Threat actor: External
Regulator citations: Notified the Office of the New Hampshire Attorney General

During the incident: Launched an internal investigation
Engaged a third-party cybersecurity firm to contain the threat, support the investigation, and determine the scope of the unauthorized access
Worked with an external data mining vendor to analyze the files on the systems which may have been impacted, identify the specific individuals whose personal information was present on those systems, and confirm the types of personal information potentially impacted
Notified affected individuals by U.S. Mail
Offering affected individuals twelve months of complimentary credit monitoring and other consumer protection services, including fraud loss reimbursement insurance coverage
Changes made: Implemented additional security measures
Continuing to evaluate ways to further enhance the security of its systems to minimize the likelihood of similar events occurring in the future
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 44 weeks(305 days from discovery to filing)
Compliance flags: Leak >180d
Discovery-date grounding: letter-groundedThe discovery date is the detection date narrated in the notification letter — the defensible tier.

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 9 filings · 9 states

View merged incident ↗

Massachusetts State AGSep 1 · first

Iowa State AG+10d

Oregon State AG+10d

Washington State AG+10d

Indiana State AG+10d

California State AG+10d

Vermont State AG+11d

Texas State AG+14d

New Hampshire State AG+17d · this page

Pattern: first filing Sep 1 (MA), last Sep 18 (NH) — a 17-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/cornerstone-staffing-solutions-20260918.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Sep 18, 2026
Raw hash: 8e8e2a653c47564cb53a1309fbf8cb9defb06debce257fa026a4b698f2b9db06

Linked disclosures

Ransomware claims (1)

Regulatory filings (8) · sorted by filing gap

Reporting entityCornerStone Staffing Solutions, Inc.

Victim entityCornerStone Staffing Solutions, Inc.

Incidentdiscovered Nov 17, 2025

Stated responseLaunched an internal investigation

ComplianceLeak >180d

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov