TonyBai

Jun 25, 2026 · Information Security

Why Go 1.27 UUIDv7 Generates Predictable “7000” Values in Browsers

In Go 1.27 the standard uuid.NewV7() function produces UUIDs with a constant “7000” segment when compiled to WebAssembly, because browsers deliberately reduce high‑precision timers for Spectre‑style mitigations, causing the 12‑bit random field to collapse to zero and dramatically lowering entropy and collision resistance.