Q: Given the following code slice:
```
1 mobile::Module FlatbufferLoader::parseModule(
2     mobile::serialization::Module* module,
4   module_ = module;
22   mobile_ivalue_size_ = module_->mobile_ivalue_size();
23   if (mobile_ivalue_size_ == 0) {```
which has a CWE-125 vulnerability at line:
```
23   if (mobile_ivalue_size_ == 0) {
```
Please analyze the root cause of the vulnerability.