People search Substack data breach timeline because the brand sits on billions of accounts, credentials, and cloud workloads. BreachHistory indexes 2 Substack-linked incidents, with headline counts up to 697K+ in catalog rows. This page maps every attested event through 2026 with internal links to canonical records.
Why Substack breach history matters
Substack operates in Software. Across indexed rows, recurring themes include unverified actor or scraping claims. Understanding the chronological pattern helps security teams, customers, and regulators separate confirmed disclosures from forum marketing.
Full timeline through 2026
2026 — BreachForums leak, 697,313 records
Cataloged incident. Substack confirmed breach Feb 2026; data accessed Oct 2025. Hacker leaked 697,313 records on BreachForums: full names, emails, phones, user IDs, Stripe customer IDs, profile pictures, bios, subscription metadata. Passwords and financial data not compromised. Exposed categories include Names; emails; phones; user IDs; Stripe IDs; profile pics; bios; subscription metadata. BreachHistory cites approximately 697K+ affected records in this row. See the substack2026-breachforums and canonical BreachHistory entry.
2025 — ~697K records (Oct 2025, discovered Feb 2026)
Cataloged incident. Substack experienced unauthorized access in October 2025 via system weakness; discovered Feb 3, 2026. Threat actor leaked ~697K-record database on BreachForums Feb 2. Exposed: emails, phone numbers, user IDs, names, profile pictures, bios, account creation dates, social media handles, Stripe IDs. Passwords and financial data not compromised. CEO Chris Best apologized; vulnerability patched. Exposed categories include Emails, phone numbers, user IDs, names, profile pictures, bios, Stripe IDs. BreachHistory cites approximately 697K+ affected records in this row. See the substack2025 and canonical BreachHistory entry.
Patterns and analysis
- Unverified actor or scraping claims — appears across multiple Substack catalog entries; prioritize controls that address this class of failure.
- Record-count hygiene — BreachHistory indexes actor-cited figures separately from company-confirmed totals; read each row's technicalWriteup before treating counts as fact.
- 2026 monitoring — New disclosures roll into this timeline as they are verified or labeled unverified per catalog policy.
What to do if you may be affected
- Step 1: Enable phishing-resistant MFA on every account tied to this brand.
- Step 2: Use unique passwords and a password manager—breach rows often involve credential reuse.
- Step 3: Monitor official company breach notices and regulator filings, not dark-web downloads.
- Step 4: Bookmark the Substack company page for new 2026+ disclosures.
Canonical BreachHistory hub
Explore every indexed row: breachhistory.com/substack · Latest: substack2026-breachforums.
Sources: BreachHistory catalog (2 rows for Substack), company and regulator disclosures cited in individual breach records.