Juspay Hyperswitch through 1.128.0 (and builds before 2026.10.19.0) contains a missing authorization vulnerability that allows unauthenticated attackers to confirm payouts with any client_secret via POST /payouts/{payout_id}/confirm. Attackers holding the merchant's publishable key and a payout_id can confirm payouts and overwrite amount, currency, connector, and routing fields to trigger unauthorized merchant payouts.
CWE-639