Q: Given the following code slice:
```
1 int
2 nvkm_firmware_ctor(const struct nvkm_firmware_func *func, const char *name,
3 		   struct nvkm_device *device, const void *src, int len, struct nvkm_firmware *fw)
5 	fw->func = func;
6 	fw->name = name;
7 	fw->device = device;
8 	fw->len = len;
10 	switch (fw->func->type) {
12 		fw->img = kmemdup(src, fw->len, GFP_KERNEL);
15 		len = ALIGN(fw->len, PAGE_SIZE);```
which has a CWE-476 vulnerability at line:
```
15 		len = ALIGN(fw->len, PAGE_SIZE);
```
Please analyze the root cause of the vulnerability.