HackingTechnologyHealthcareInformationStolen CredentialsData ExfiltratedCustomer Data InvolvedEmployee Data InvolvedIdentity (basic)Government IDHealth (basic)Financial accountCredentialsMediumContained

CYTEK BIOSCIENCES, INC.

bd_f10136bccf81d097 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Nov 5, 2025

Filed

Dec 22, 2025

To disclose

7 weeks

Affected

3state residents only

Linked

6 records

Confidence

66%

Full breach record for CYTEK BIOSCIENCES, INC. →

Cytek Biosciences, Inc. notified the New Hampshire Attorney General of a security incident involving unauthorized access to systems affecting 3 New Hampshire residents. The breach occurred around November 1, 2025, and was discovered on November 5, 2025. Personal information of Cytek employees, including names, SSNs, health data, and credentials, was accessed. Cytek engaged forensic investigators, reported to law enforcement, and offered 24 months of credit monitoring.

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Incident timeline

undetected · 4 days

discovery → filing · 7 weeks / 47 days

Nov 1, 2025

Begins

Nov 5, 2025

Discovered

Dec 22, 2025

Filed

vs. sector median

4 wks faster

This filing is one of 6 records about the same incident.View merged incident

Linked disclosures

Why this link?

Ransomware claims (2)

Leak Sitecmdorganizationbd_c1046e1115ba4f232026-01-25 · +34dVerified by operator
Leak Siterhysidabd_b141b6898f0871ed2025-11-01 · +51dVerified by operator

Regulatory filings (3) · sorted by filing gap

Indiana State AGbd_1553fa181e3ff4fd2025-12-22Verified
Maine State AGbd_1ee03444beb455432025-12-22Verified by operator
Massachusetts State AGbd_4edcb8da3a812e572025-12-22Verified by operator

Name: CYTEK BIOSCIENCES, INC.
norm: cytek biosciences
Domain: cytekbio.com

Name: CYTEK BIOSCIENCES, INC.
norm: cytek biosciences
Domain: cytekbio.com
Industry: TechnologyllmHealthcarellm

Discovered: Nov 5, 2025
Breach occurred: Nov 1, 2025
Undetected for: 4 daysoccurrence → discovery
Materiality determined: —
Notification sent: Dec 22, 2025
Affected individuals: 3state-resident count only
Data types: Identity (basic)Government IDHealth (basic)Financial accountCredentials
Data elements: Social Security numberDate of birthMedical information
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing ApplicationT1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: reporting the issue to law enforcementnotified Attorney General John M. Formella
Initial access: valid_credentials

During the incident: Taking certain of its systems offline
Engaged third- party forensic investigators to assist in its investigation of the issue
Took additional steps to enhance the security of its systems
Reporting the issue to law enforcement
Initiating an internal investigation
Deploying endpoint detection and response tools
Implementing additional technical measures to prevent similar attacks
Changes made: Taking certain of its systems offline
Engaged third- party forensic investigators to assist in its investigation of the issue
Took additional steps to enhance the security of its systems
Reporting the issue to law enforcement
Initiating an internal investigation
Deploying endpoint detection and response tools
Implementing additional technical measures to prevent similar attacks
Offering 24 months of identity protection services and credit monitoring from a leading identity monitoring services company, Experian
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 7 weeks(47 days from discovery to filing)
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 AGDec 22 · first

Maine State AGDec 22 · first

Massachusetts State AGDec 22 · first

New Hampshire State AGDec 22 · 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://mm.nh.gov/files/uploads/doj/remote-docs/cytek-biosciences-20251222.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Dec 22, 2025
Raw hash: 18097d921280c9366343bc2463894bb5cfa3c99a45a2db0b9a3cfb2326373bd0

Linked disclosures

Ransomware claims (2)

Regulatory filings (3) · sorted by filing gap

Reporting entityCYTEK BIOSCIENCES, INC.

Victim entityCYTEK BIOSCIENCES, INC.

Incidentdiscovered Nov 5, 2025

Stated responseTaking certain of its systems offline

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancemm.nh.gov