Hack history / 2025 / Hack or exploit
Cozy V2
Hack or exploit on Aug 30, 2025 · Missing Input Validation
ONE SOURCE · 1 SOURCE
Lost
$427K
dollars at the time
Returned
none listed
as the sources state it
Rank
#1,202
among thefts by dollars lost
What happened
Cozy Finance lost $427K on August 29, 2025 on Optimism when completeWithdraw function lacked caller verification, letting attacker complete withdrawals using only a user's redemption ID.
Details
- Date
- Aug 30, 2025
- Kind
- Hack or exploit
- Method
- Missing Input Validation
- How in
- Smart contract bug
- Target
- DeFi protocol
- Chains
- Optimism
Reported by
Related incidents
Cozy V2 2026 · Hack or exploit · $160K
Silo Finance 2025 · Hack or exploit · $546K
Usual USD0 2025 · Hack or exploit · $43K
Silo Finance 2025 · Hack or exploit · $546K
Usual USD0 2025 · Hack or exploit · $43K
Cite this page
SwanBluechip, "Cozy V2 hack, Aug 30, 2025: $427K lost", Crypto hack history, https://swan-hack-tracker.pages.dev/history/i/ht258f1a9fed/ (data as of 2026-11-01).