HackingTechnologyInformationData ExfiltratedCustomer Data InvolvedPIIIdentity (basic)LowContained

MASTEC, INC.

bd_d93b0d10e9a7baae · schema v1 · pii pii-v1

Severity

Low

Discovered

Oct 1, 2025

Filed

Jun 5, 2026

To disclose

35 weeks

Affected

Not disclosed

Linked

9 filings

Confidence

64%

Full breach record for MASTEC, INC. →2 incidents on file

MasTec, Inc. reported a data security event in South Carolina involving unauthorized access to a portion of its computer network in August 2025. The breach affected personal information of individuals, including 73 Rhode Island residents. MasTec engaged third-party cybersecurity experts and law enforcement, and is offering complimentary credit and identity-theft monitoring services to affected individuals.

J jump to incidentP pin to compareR raw source

Leak gap clock✗ Leak >180d35 weeks discovery → filing

⚠ unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Incident timeline

undetected · 61 days

discovery → filing · 35 weeks / 247 days

Aug 1, 2025

Begins

Oct 1, 2025

Discovered

Jun 5, 2026

Filed

vs. sector median

+17 wks slower

This filing is one of 9 about the same incident.View merged incident

A leak claim by cl0p about this victim predates this filing by 216 days.View originating leak claim

Linked disclosures

Why this link?

Ransomware claims (1)

Leak Sitecl0pbd_077ee15e6166ed792025-10-31 · +216dVerified by operator

Regulatory filings (7) · sorted by filing gap

Vermont State AGbd_17006039c927389d2026-06-05Verified
Indiana State AGbd_2337a1feed74d7a42026-06-05Verified
Nebraska State AGbd_69df7fd6f827f7472026-06-05Verified
Maine State AGbd_b14ee6c6db7a57262026-06-05Verified

Show 3 more filings ↓up to 4d gap

New Hampshire State AGbd_9a55bbe733ae71cb2026-06-04 · +1dCandidate
Texas State AGbd_2db96186099527c32026-06-09 · +4dVerified
Massachusetts State AGbd_fa5d678c3d2160372026-06-09 · +4dVerified

Name: MASTEC, INC.
norm: mastec
Domain: mastec.com

Name: MASTEC, INC.
norm: mastec
Domain: mastec.com
Industry: Technologyllm

Discovered: Oct 1, 2025
Breach occurred: Aug 1, 2025 – Aug 31, 2025
Undetected for: 61 daysoccurrence → discovery
Materiality determined: —
Notification sent: May 11, 2026
Affected individuals: Not disclosed
Data types: PIIIdentity (basic)
Attack vector: Unauthorized Access
MITRE ATT&CK: T1190 Exploit Public-Facing Application
Threat actor: External
Regulator citations: notified law enforcement
Initial access: exploit_public_facing

During the incident: Worked with third-party experts to address this event
Perform an investigation into the unauthorized activity
Engaged a data-review firm to analyze those files’ contents
Notified law enforcement
Changes made: Further secure our systems to protect your information
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 35 weeks(247 days from discovery to filing)
Compliance flags: Leak >180d
Discovery-date grounding: unattributedNo provenance was recorded for this discovery date and it matches no other date on the record. It may be correct, but it is not independently grounded.

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 8 filings · 8 states

View merged incident ↗

New Hampshire State AGJun 4 · first

South Carolina State AG+1d · this page

Texas State AG+5d

Massachusetts State AG+5d

Pattern: first filing Jun 4 (NH), last Jun 9 (MA) — a 5-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://consumer.sc.gov/sites/consumer/files/Documents/Security%20Breach%20Notices/2026/Consumer%20Letter%20-%20MasTec.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 5, 2026
Raw hash: 014004ad47f34ea1ae987f55ce2d1dedd6d217db97f64d240a9a509b0ca59bb7

Linked disclosures

Ransomware claims (1)

Regulatory filings (7) · sorted by filing gap

Reporting entityMASTEC, INC.

Victim entityMASTEC, INC.

Incidentdiscovered Oct 1, 2025

Stated responseWorked with third-party experts to address this event

ComplianceLeak >180d

Extraction provenanceno artifact recorded

Source provenanceconsumer.sc.gov