int mif_encode(jas_image_t *image, jas_stream_t *out, char *optstr)
{
	mif_hdr_t *hdr;
	jas_image_t *tmpimage;
	int fmt;
	int cmptno;
	mif_cmpt_t *cmpt;
	jas_image_cmptparm_t cmptparm;
	jas_seq2d_t *data;
	int_fast32_t x;
	int_fast32_t y;
	int bias;

	hdr = 0;
	tmpimage = 0;
	data = 0;

	if (optstr && *optstr != '\0') {
		jas_eprintf("warning: ignoring unsupported options\n");
	}

	if ((fmt = jas_image_strtofmt("pnm")) < 0) {
		jas_eprintf("error: PNM support required\n");
		goto error;
	}

	if (!(hdr = mif_makehdrfromimage(image))) {
		goto error;
	}
	if (mif_hdr_put(hdr, out)) {
		goto error;
	}

	/* Output component data. */
	for (cmptno = 0; cmptno < hdr->numcmpts; ++cmptno) {
		cmpt = hdr->cmpts[cmptno];
		if (!cmpt->data) {
			if (!(tmpimage = jas_image_create0())) {
				goto error;
			}	
			cmptparm.tlx = 0;
			cmptparm.tly = 0;
			cmptparm.hstep = cmpt->sampperx;
			cmptparm.vstep = cmpt->samppery;
			cmptparm.width = cmpt->width;
			cmptparm.height = cmpt->height;
			cmptparm.prec = cmpt->prec;
			cmptparm.sgnd = false;
			if (jas_image_addcmpt(tmpimage, jas_image_numcmpts(tmpimage), &cmptparm)) {
				goto error;
			}
			if (!(data = jas_seq2d_create(0, 0, cmpt->width, cmpt->height))) {
				goto error;
			}
			if (jas_image_readcmpt(image, cmptno, 0, 0, cmpt->width, cmpt->height,
			  data)) {
				goto error;
			}
			if (cmpt->sgnd) {
				bias = 1 << (cmpt->prec - 1);
				for (y = 0; y < cmpt->height; ++y) {
					for (x = 0; x < cmpt->width; ++x) {
						*jas_seq2d_getref(data, x, y) += bias;
					}
				}
			}
			if (jas_image_writecmpt(tmpimage, 0, 0, 0, cmpt->width, cmpt->height,
			  data)) {
				goto error;
			}
			jas_seq2d_destroy(data);
			data = 0;
			if (jas_image_encode(tmpimage, out, fmt, 0)) {
				goto error;
			}
			jas_image_destroy(tmpimage);
			tmpimage = 0;
		}
	}

	mif_hdr_destroy(hdr);

	return 0;

error:
	if (hdr) {
		mif_hdr_destroy(hdr);
	}
	if (tmpimage) {
		jas_image_destroy(tmpimage);
	}
	if (data) {
		jas_seq2d_destroy(data);
	}
	return -1;
}

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.