Passkey Redaction Attacks Subvert GitHub, Microsoft Authentication

**Executive summary:** The report explains how adversary-in-the-middle (AitM) attackers can proxy and modify login pages to remove passkey authentication options (authentication method redaction), forcing users to use less-secure fallback methods that allow capture of credentials and tokens; it provides PoC examples against GitHub and Microsoft and recommends mitigations including magic/warded links, conditional access and device-based enforcement, and requiring or encouraging multiple passkeys.