People search Frost Bank data breach timeline because regulated data and trust are existential—one incident triggers class actions and regulator exams. BreachHistory indexes 2 Frost Bank-linked incidents, with headline counts up to 109K+ in catalog rows. This page maps every attested event through 2026 with internal links to canonical records.
Why Frost Bank breach history matters
Frost Bank operates in Financial Services (United States). Across indexed rows, recurring themes include ransomware and extortion, third-party and supply-chain exposure. Understanding the chronological pattern helps security teams, customers, and regulators separate confirmed disclosures from forum marketing.
Full timeline through 2026
2026 — California AG data breach notification
Cataloged incident. Frost Bank appears on the California Attorney General data breach notification list (reported 2026-05-20). Breach period noted as: 12/06/2025. Record counts and exposed data types are often not published in the initial AG listing; consult the linked sample notification on the AG site when available. Exposed categories include Not specified in AG list export; see organization sample notification. No attested victim count is published for this row yet. See the cullenfrost-2026-ca-20260520 and canonical BreachHistory entry.
2026 — Frost Bank - vendor breach and Everest-linked lawsuit allegations affecting ~109k customers
Unverified claim — treat actor counts cautiously. Security Boulevard/CISO Whisperer reported that Frost Bank faced two proposed class-action lawsuits after a cyberattack attributed in the complaints to the Everest ransomware group allegedly exposed sensitive data for about 109,000 customers. Frost said it had been notified by a third-party vendor of unauthorized access to the vendor's systems that may have included Frost customer data, and said there was no evidence of unauthorized access to Frost's own network. The affected count and detailed fields were lawsuit Exposed categories include Alleged Social Security numbers, financial account information, and contact information. BreachHistory cites approximately 109K+ affected records in this row. See the frost-bank2026-vendor-everest and canonical BreachHistory entry.
Patterns and analysis
- Ransomware and extortion — appears across multiple Frost Bank catalog entries; prioritize controls that address this class of failure.
- Third-party and supply-chain exposure — appears across multiple Frost Bank 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: Freeze credit and enable fraud alerts if notification letters cite SSN or account numbers.
- Step 5: Bookmark the Frost Bank company page for new 2026+ disclosures.
Canonical BreachHistory hub
Explore every indexed row: breachhistory.com/cullenfrost · Latest: cullenfrost-2026-ca-20260520.
Sources: BreachHistory catalog (2 rows for Frost Bank), company and regulator disclosures cited in individual breach records.