[Duplicate] Open Redirect Flow Abuse via OAuth Validation Bypass

Summary

A critical Open Redirect vulnerability was identified within an OAuth authorization flow endpoint. The vulnerability occurs because the callback_url (or equivalent redirect parameter) is validated using an insecure string prefix match instead of exact parsing. An attacker can craft a specific URL containing a malicious domain that technically starts with the whitelisted string but resolves to the attacker's server (e.g., using authority confusion https://trusted.com@attacker.com/). The redirect, being part of an OAuth flow, could potentially leak sensitive response parameters to the attacker if chained with an authorization request.

Vulnerability Details

Vulnerability Type: Open Redirect — OAuth callback validation bypass Affected Component: OAuth Authorization Flow / Client Callback Validation Affected Mechanism: Weak string matching (startsWith or similar prefix validation)