static void FillGifBackGround(struct ngiflib_gif * g) {
	long n = (long)g->width*g->height;
#ifndef NGIFLIB_INDEXED_ONLY
	u32 bg_truecolor;
#endif /* NGIFLIB_INDEXED_ONLY */

	if((g->frbuff.p8==NULL)||(g->palette==NULL)) return;
#ifndef NGIFLIB_INDEXED_ONLY
	if(g->mode & NGIFLIB_MODE_INDEXED) {
#endif /* NGIFLIB_INDEXED_ONLY */
		ngiflib_memset(g->frbuff.p8, g->backgroundindex, n);
#ifndef NGIFLIB_INDEXED_ONLY
	} else {
		u32 * p = g->frbuff.p32;
		bg_truecolor = GifIndexToTrueColor(g->palette, g->backgroundindex);
		while(n-->0) *p++ = bg_truecolor;
	}
#endif /* NGIFLIB_INDEXED_ONLY */
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.