Nucor

Disclosed May 14, 20252,461 affectedConfirmed

Cyberattack forces steelmaker Nucor to halt some production

Nucor told the SEC it identified unauthorized third-party access to some IT systems and temporarily halted production at various locations as a precaution.

What is known

People affected	2,461 (as reported by the organization)
Disclosed	May 14, 2025
Happened	May 3, 2025
Attack	Hacking
Data exposed	Not stated
Sector	Manufacturing · US
Status	Confirmed

Sources

SEC filingsec.gov

Nucor Corp Form 8-K/A, Item 1.05 (2025-06-20)

SEC filingsec.gov

Nucor Corp Form 8-K, Item 1.05 (2025-05-14)

Official noticeago.vermont.gov

Vermont Attorney General: 2025-06-24 Nucor Corporation Data Breach Notice to Consumers

Official noticein.gov

Indiana Attorney General 2025 data breach report: Nucor

Notices filed

TotalMay 14, 2025

SEC 8-KCount not stated

TotalMay 14, 2025

ResearchCount not stated

TotalJun 20, 2025

SEC 8-KCount not stated

Residents of VTJun 24, 2025

Vermont AGCount not stated

Residents of INJun 24, 2025

Indiana AG32 people

Other breaches at Nucor

Breach, details not statedBreach notice filed with the Indiana AG, details not stated.8,824 affectedManufacturingUSJun 30, 2023

History of this record

records_basis2026-09-25

empty to organizationby backfillSource

records2026-09-25

empty to 2461by backfillSource

occurred2026-09-25

empty to 2025-05-03by backfillSource

source2026-09-25

empty to https://ago.vermont.gov/document/2025-06-24-nucor-corporation-data-breach-notice-consumersby backfillSource

sector2026-09-25

other to manufacturingby seedSource

attack2026-09-25

unknown to hackingby seedSource

summary2026-09-25

empty to Nucor told the SEC it identified unauthorized third-party access to some IT systems and temporarily halted production at various locations as a precaution.by seedSource

title2026-09-25

Updated SEC filing on a material cybersecurity incident to Cyberattack forces steelmaker Nucor to halt some productionby seedSource

disclosed2026-09-25

2025-06-20 to 2025-05-14by backfillSource

Added2026-09-25

First recordedby backfillSource

First seen 2026-09-25 (SEC 8-K), confirmed by SEC 8-K. Record counts are as reported. Not legal advice.

Everything about Nucor