NetEase Cloud Music client for Windows (cloudmusic.exe) versions 3.1.38 and 3.1.39.205426 contains a TLS certificate validation vulnerability that allows a network-adjacent attacker to intercept and decrypt HTTPS traffic by failing to validate the server certificate chain, verify the hostname, or consult any Windows certificate trust store. Attackers can perform a man-in-the-middle attack using a rogue certificate authority to decrypt traffic, capture the MUSIC_U session credential sent in authenticated API requests, and modify server responses in transit, enabling account takeover and transport-layer response forgery.