HackingTechnologyInformationCustomer Data InvolvedEmployee Data InvolvedIdentity (basic)Government IDFinancial accountHealth (basic)CredentialsMediumContained

CYTEK BIOSCIENCES, INC.

bd_1ee03444beb45543 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Nov 28, 2025

Filed

Dec 22, 2025

To disclose

24 days

Affected · nationwide

3311 in this filing

Linked

7 filings

Confidence

66%

Full breach record for CYTEK BIOSCIENCES, INC. →

Cytek Biosciences, Inc. reported an external system breach (hacking) occurring on November 1, 2025, discovered on November 28, 2025. The incident affected 331 individuals, exposing names, contact info, SSNs, driver's licenses, health data, financial accounts, and credentials. Cytek engaged forensic investigators, reported to law enforcement, and offered 24 months of identity protection services.

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Leak gap clock⏱ Leak >30d24 days discovery → filing

⚠ AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline

undetected · 27 days

discovery → filing · 24 days

Nov 1, 2025

Begins

Nov 28, 2025

Discovered

Dec 22, 2025

Filed

vs. sector median

15 wks faster

This filing is one of 7 about the same incident.View merged incident

Linked disclosures

Why this link?

Ransomware claims (3)

Leak Siterhysidabd_eb75b2e7b9fce6802026-01-25 · +35dVerified by operator
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
Massachusetts State AGbd_4edcb8da3a812e572025-12-22Verified by operator
New Hampshire State AGbd_f10136bccf81d0972025-12-22Verified

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

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

Discovered: Nov 28, 2025
Breach occurred: Nov 1, 2025
Undetected for: 27 daysoccurrence → discovery
Materiality determined: —
Notification sent: Dec 22, 2025
Affected individuals: 331state + nationwide
Data types: Identity (basic)Government IDFinancial accountHealth (basic)Credentials
Data elements: Date of birthMedical information
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing Application
Threat actor: ExternalFinancial
Regulator citations: Filed notification with Maine Attorney General
Initial access: exploit_public_facing

During the incident: Took certain of our systems offline
Engaged third-party forensic investigators
Enhanced the security of our systems
Reported the issue to law enforcement
Changes made: Enhanced the security of our systems
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 24 days(24 days from discovery to filing)
Compliance flags: Leak >30dClock withheld · confirmation date

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 4 filings · 4 states

View merged incident ↗

Indiana State AGDec 22 · first

Massachusetts State AGDec 22 · first

New Hampshire State AGDec 22 · first

Maine 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://www.maine.gov/agviewer/content/ag/985235c7-cb95-4be2-8792-a1252b4f8318/37b0bb9e-101d-4580-a543-6d58c3cd7d40.html
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: c24c1fbcf7440c0b9f1db39759001b3451ff7aa2217200a8ff93ffd1b57a58de

Linked disclosures

Ransomware claims (3)

Regulatory filings (3) · sorted by filing gap

Reporting entityCYTEK BIOSCIENCES, INC.

Victim entityCYTEK BIOSCIENCES, INC.

Incidentdiscovered Nov 28, 2025

Stated responseTook certain of our systems offline

ComplianceLeak >30d

Extraction provenanceno artifact recorded

Source provenancewww.maine.gov