Sunshine is a self-hosted game stream host for Moonlight. In 0.23.1 and earlier, Sunshines pairing protocol implementation does not validate request order and is thereby vulnerable to a MITM attack, potentially allowing an unauthenticated attacker to pair a client by hijacking a legitimate pairing attempt. This bug may also be used by a remote attacker to crash Sunshine. This vulnerability is fixed in 2025.118.151840.
The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.