gorilla/websocket used math/rand (cryptographically weak pseudo-random number generator) to generate WebSocket frame mask keys prior to commit d67f4185. WebSocket masking keys MUST be unpredictable to prevent frame content injection attacks. math/rand produces deterministic output when seeded with a known value, enabling an attacker to predict or recover mask keys and inject content into WebSocket connections.

Type: Use of Cryptographically Weak Pseudo-Random Number Generator Fix: Replaced math/rand with crypto/rand (commit d67f4185, released in v1.5.3) Credit: bounty-hunter v6.0 silent-fix detection