Nucor
Disclosed May 14, 20251 year ago2,461 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
| Source | |
|---|---|
| Nucor Corp Form 8-K/A, Item 1.05 (2025-06-20)sec.gov · SEC filing | SEC filing |
| Nucor Corp Form 8-K, Item 1.05 (2025-05-14)sec.gov · SEC filing | SEC filing |
| Vermont Attorney General: 2025-06-24 Nucor Corporation Data Breach Notice to Consumersago.vermont.gov · Official notice | Official notice |
| Indiana Attorney General 2025 data breach report: Nucorin.gov · Official notice | Official notice |
Notices filed
| Where | Filed | People |
|---|---|---|
| SEC 8-Ktotal | May 14, 2025 | |
| Researchtotal | May 14, 2025 | |
| SEC 8-Ktotal | Jun 20, 2025 | |
| Vermont AGresidents of VT | Jun 24, 2025 | |
| Indiana AGresidents of IN | Jun 24, 2025 | 32 |
Other breaches at Nucor
| Breach | Affected | ||||
|---|---|---|---|---|---|
| Disclosed Jun 30, 2023Jun 30, 20233 years ago | Jun 30, 20233 years ago | Not stated | Manufacturing | Confirmed | 8,824 |
History of this record
- 2026-09-25 · records_basis: empty to organization · backfill source
- 2026-09-25 · records: empty to 2461 · backfill source
- 2026-09-25 · occurred: empty to 2025-05-03 · backfill source
- 2026-09-25 · source: empty to https://ago.vermont.gov/document/2025-06-24-nucor-corporation-data-breach-notice-consumers · backfill source
- 2026-09-25 · sector: other to manufacturing · seed source
- 2026-09-25 · attack: unknown to hacking · seed source
- 2026-09-25 · summary: 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. · seed source
- 2026-09-25 · title: Updated SEC filing on a material cybersecurity incident to Cyberattack forces steelmaker Nucor to halt some production · seed source
- 2026-09-25 · disclosed: 2025-06-20 to 2025-05-14 · backfill source
- 2026-09-25 · added · backfill source
First seen 2026-09-25 (SEC 8-K), confirmed by SEC 8-K. Record counts are as reported. Not legal advice.