BIT-PILLOW-2026-112898 Pillow: Image.quantize() with empty palette leaks uninitialized stack memory

Pillow is a Python imaging library. From 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize uses an empty palette. ImagingPaletteCacheUpdate leaves a local cache array uninitialized when the palette has zero entries, and the conversion path emits those bytes as...