Q: Given the following code slice:
```
1 static int jpc_dec_process_siz(jpc_dec_t *dec, jpc_ms_t *ms)
3 	jpc_siz_t *siz = &ms->parms.siz;
12 	dec->xstart = siz->xoff;
13 	dec->ystart = siz->yoff;
14 	dec->xend = siz->width;
15 	dec->yend = siz->height;
16 	dec->tilewidth = siz->tilewidth;
17 	dec->tileheight = siz->tileheight;
18 	dec->tilexoff = siz->tilexoff;
19 	dec->tileyoff = siz->tileyoff;
20 	dec->numcomps = siz->numcomps;
21 	if (!(dec->cp = jpc_dec_cp_create(dec->numcomps))) {
25 	if (!(dec->cmpts = jas_alloc2(dec->numcomps, sizeof(jpc_dec_cmpt_t)))) {
43 	dec->image = 0;
45 	dec->numhtiles = JPC_CEILDIV(dec->xend - dec->tilexoff, dec->tilewidth);
46 	dec->numvtiles = JPC_CEILDIV(dec->yend - dec->tileyoff, dec->tileheight);
47 	dec->numtiles = dec->numhtiles * dec->numvtiles;```
which has a CWE-190 vulnerability at line:
```
47 	dec->numtiles = dec->numhtiles * dec->numvtiles;
```
Please analyze the root cause of the vulnerability.