CyrusOne data breach exposes 373,460 accounts
CyrusOne
Data centre operator CyrusOne experienced a breach on August 5, 2026, with attackers publishing roughly 373,000 email addresses and associated corporate contact details. The exposed data included names, phone numbers, physical addresses and support tickets.
why this severityConfirmed breach exposing personal data of over 370k accounts
- first report
- 7 Oct 2026
- last update
- 7 Oct 2026
What to do
Investigate the breach, notify affected users, and improve security controls
Timeline · 1
Sources · 1
News and write-ups
- 2026-10-07CyrusOne data breach exposes 373,460 accountsHave I Been Pwned · haveibeenpwned.com/Breach/CyrusOne
Titles and links belong to their publishers. The summary above is written by gcdRadar in its own words; data is CC BY-SA 4.0.
Classification
- AI role
- No AI role
- categories
- General security
- severity
- 4 · Confirmed real-world loss
- targets
- Not applicable
- owasp llm top 10
- no entry for these categories
- mitre atlas
- no technique for these categories
- dates
- happened 5 Aug 2026 · first reported 7 Oct 2026
- origin
- News & research feeds
- record
- confidence 0.95 · created 2026-10-26 14:52Z · updated 2026-10-30 03:33Z
Lane, AI role, categories and severity come from the classifier; the OWASP and ATLAS rows are derived from the categories. How these are assigned
Copy a brief
This record as a short Markdown brief, for a ticket, a chat or a coding agent.
the brief as text
# CyrusOne data breach exposes 373,460 accounts https://gcdradar.vercel.app/incidents/cyrusone-data-breach-exposes-373-460-accounts · AIR-2026-1519 · closed 2026-10-21 - Lane: Breaches & attacks - Severity: 4 (Confirmed real-world loss): Confirmed breach exposing personal data of over 370k accounts - Fix status: No fix needed - First reported: 2026-10-07 (happened 2026-08-05) - AI role: No AI role - Products: CyrusOne ## Summary Data centre operator CyrusOne experienced a breach on August 5, 2026, with attackers publishing roughly 373,000 email addresses and associated corporate contact details. The exposed data included names, phone numbers, physical addresses and support tickets. ## What to do Investigate the breach, notify affected users, and improve security controls ## Latest updates - 2026-10-07: CyrusOne data breach exposes 373,460 accounts (https://haveibeenpwned.com/Breach/CyrusOne) ## Sources - 2026-10-07 Have I Been Pwned: CyrusOne data breach exposes 373,460 accounts https://haveibeenpwned.com/Breach/CyrusOne Verify against the vendor's advisory before changing production. Data CC BY-SA 4.0, https://gcdradar.vercel.app.
Related
- live7.5SonicOS SSLVPN CVE-2026-19868: SonicWall SonicOS SSLVPN MFA Bypass
Patch now · Exploited · Patched · since 6 Nov 2026 · updated 9 Nov 2026 · CVE-2026-19868
- liveGitHub repositories Fake security tools on GitHub push backdoors and infostealers
Supply chain · Exploited · No fix needed · since 6 Nov 2026
- liveQNAP NAS QNAP warns of Plex2Shell attacks exploiting Plex Media Server on NAS devices
Patch now · Exploited · No patch yet · since 6 Nov 2026 · updated 9 Nov 2026
- liveFBI Agent Pleads Guilty to Stealing Cryptocurrency from Hackers
Breaches & attacks · Real loss · since 6 Nov 2026 · updated 9 Nov 2026
- liveMicrosoft Paint CVE-2026-83844: Microsoft Paint RCE Flaw Fixed via Microsoft Store
Patch now · Disclosed · Patched · since 6 Nov 2026 · updated 9 Nov 2026 · CVE-2026-83844
- liveRefrigeration system controllers US Agencies Warn Threat Actors Target Commercial Refrigeration Systems
Breaches & attacks · Exploited · since 6 Nov 2026 · updated 9 Nov 2026