The vulnerability stems from unsafe YAML deserialization due to missing SafeConstructor configuration. The commit diff shows both YamlFileLoader and YamlTextLoader classes were modified to replace 'new Yaml()' with 'new Yaml(new SafeConstructor())'. Prior to this fix, the default snakeyaml parser would allow instantiation of arbitrary Java types via YAML payloads. These two functions directly handle YAML parsing for the plugin's axis configuration, making them the entry points for exploitation. The high confidence comes from explicit evidence in the patch and CWE-502 classification.