OpenImageIO: TGA-to-GIF palette split signed overflow causes SIGSEGV

OpenImageIO is a toolset for reading, writing, and manipulating image files of any image file format relevant to VFX / animation. Prior to 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1, A truncated tga can leave a pending gif frame that is processed during output close. gifsplitpalette() computes numpixels multiplied by the palette partition width in signed 32-bit arithmetic; a large image overflows that intermediate, corrupts subpixelsa, and drives an out-of-bounds read while building the gif palette, resulting in a process crash and denial of service. The affected implementation is identified by src/gif.imageio/gif.h, GifSplitPalette(), numPixels, subPixelsA, GIFOutput, and truncated TGA input, which define the relevant source path, functions, state, and trigger. This issue is fixed in versions 3.0.21.0, 3.1.16.0, and 3.2.0.3-beta1.