GHSA-VPXV-R9PG-7GPR ImageMagick has Global Buffer Overflow (OOB Read) via Negative Pixel Index in UIL and XPM Writer

The UIL and XPM image encoder do not validate the pixel index value returned by GetPixelIndex before using it as an array subscript. In HDRI builds, Quantum is a floating-point type, so pixel index values can be negative. An attacker can craft an image with negative pixel index values to trigger ...