15 Costliest Credential Stuffing Attack Examples of the Decade (and the Authentication Lessons They Teach)

This report reviews 15 high-profile credential-stuffing incidents across industries (including Snowflake/Ticketmaster, 23andMe, Roku, and others), demonstrates a consistent root cause—password reuse and systems that accept single-factor authentication—and recommends rapid adoption of phishing-resistant passwordless authentication (FIDO2/passkeys or hardware tokens), stronger MFA, rate limiting, and vendor access controls to prevent large-scale account takeover, downstream data exposure, and regulatory penalties.