HackingHealthcareHealthcareCustomer Data InvolvedData ExfiltratedPHIGovernment IDIdentity (basic)Health (basic)MediumContained

Bayside Dental

bd_9baf37cb38f7338f · schema v1 · pii pii-v1

Severity

Medium

Discovered

Jan 5, 2026

Filed

Apr 17, 2026

To disclose

15 weeks

Affected

2state residents only

Linked

5 filings

Confidence

66%

Full breach record for Bayside Dental →2 incidents on file

Bayside Dental detected unauthorized access to its network on January 5, 2026. An investigation determined that an unauthorized individual may have accessed or removed files containing personal health information, including names, dates of birth, Social Security numbers, health insurance details, and medical treatment information. The company secured its network, engaged external cybersecurity professionals, and is offering complimentary credit monitoring and fraud assistance services to affected individuals.

J jump to incidentP pin to compareR raw source

Massachusetts clock✗ MA AG >90d15 weeks discovery → filing

Incident timeline

discovery → filing · 15 weeks / 102 days

Jan 5, 2026

Begins

Jan 5, 2026

Discovered

Apr 17, 2026

Filed

vs. sector median

+3 wks slower

This filing is one of 5 about the same incident.View merged incident

A leak claim by sinobi about this victim predates this filing by 85 days.View originating leak claim

Linked disclosures

Why this link?

Ransomware claims (1)

Leak Sitesinobibd_585476fef6ea1bf72026-01-21 · +85dVerified

Regulatory filings (3) · sorted by filing gap

Washington State AGbd_6a8490a03f05ff602026-04-17Candidate
HHS OCRbd_7fa1baec43bd9dcb2026-04-17Verified
New Hampshire State AGbd_1f7eca0bd1a934922026-04-20 · +3dVerified

Name: Bayside Dental
norm: bayside dental
Domain: baysidedental.com

Name: Bayside Dental
norm: bayside dental
Domain: baysidedental.com
Industry: Healthcarellm

Discovered: Jan 5, 2026
Breach occurred: Jan 5, 2026
Undetected for: 0 daysoccurrence → discovery
Materiality determined: —
Notification sent: —
Affected individuals: 2state-resident count only
Data types: PHIGovernment IDIdentity (basic)Health (basic)
Attack vector: Unknown
MITRE ATT&CK: T1078 Valid Accounts
Threat actor: External

During the incident: Secured our network
Commenced a prompt and thorough investigation
Working very closely with external cybersecurity professionals experienced in handling these types of incidents
Conducted a thorough review of the potentially impacted data
Providing you with access to Single Bureau Credit Monitoring/Single Bureau Credit Report/Single Bureau Credit Score services at no charge
Providing you with proactive fraud assistance to help with any questions you might have or in event that you become a victim of fraud
Changes made: Continually evaluate and modify our practices and internal controls to enhance the security and privacy of your personal information
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 15 weeks(102 days from discovery to filing)
Compliance flags: MA AG >90dLeak >30d
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 · 4 filings · 3 states

View merged incident ↗

Washington State AGApr 17 · first

HHS OCRApr 17 · first

Massachusetts State AGApr 17 · first · this page

New Hampshire State AG+3d

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.mass.gov/doc/2026-601-bayside-dental/download
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: 0fe4720794c439b79c6dc42895b5cca812352c6382e7f7ff09e61cdd883d28e5

Linked disclosures

Ransomware claims (1)

Regulatory filings (3) · sorted by filing gap

Reporting entityBayside Dental

Victim entityBayside Dental

Incidentdiscovered Jan 5, 2026

Stated responseSecured our network

ComplianceMA AG >90d

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov